@article {pmid38695606,
year = {2024},
author = {Wang, X-Q and Du, K and Chen, C and Hou, P and Li, W-F and Chen, Y and Li, Q and Zhou, C-Z},
title = {Profiling the interplay and coevolution of Microcystis aeruginosa and cyanosiphophage Mic1.},
journal = {Microbiology spectrum},
volume = {},
number = {},
pages = {e0029824},
doi = {10.1128/spectrum.00298-24},
pmid = {38695606},
issn = {2165-0497},
abstract = {UNLABELLED: The cyanosiphophage Mic1 specifically infects the bloom-forming Microcystis aeruginosa FACHB 1339 from Lake Chaohu, China. Previous genomic analysis showed that its 92,627 bp double-stranded DNA genome consists of 98 putative open reading frames, 63% of which are of unknown function. Here, we investigated the transcriptome dynamics of Mic1 and its host using RNA sequencing. In the early, middle, and late phases of the 10 h lytic cycle, the Mic1 genes are sequentially expressed and could be further temporally grouped into two distinct clusters in each phase. Notably, six early genes, including gp49 that encodes a TnpB-like transposase, immediately reach the highest transcriptional level in half an hour, representing a pioneer cluster that rapidly regulates and redirects host metabolism toward the phage. An in-depth analysis of the host transcriptomic profile in response to Mic1 infection revealed significant upregulation of a polyketide synthase pathway and a type III-B CRISPR system, accompanied by moderate downregulation of the photosynthesis and key metabolism pathways. The constant increase of phage transcripts and relatively low replacement rate over the host transcripts indicated that Mic1 utilizes a unique strategy to gradually take over a small portion of host metabolism pathways after infection. In addition, genomic analysis of a less-infective Mic1 and a Mic1-resistant host strain further confirmed their dynamic interplay and coevolution via the frequent horizontal gene transfer. These findings provide insights into the mutual benefit and symbiosis of the highly polymorphic cyanobacteria M. aeruginosa and cyanophages.

IMPORTANCE: The highly polymorphic Microcystis aeruginosa is one of the predominant bloom-forming cyanobacteria in eutrophic freshwater bodies and is infected by diverse and abundant cyanophages. The presence of a large number of defense systems in M. aeruginosa genome suggests a dynamic interplay and coevolution with the cyanophages. In this study, we investigated the temporal gene expression pattern of Mic1 after infection and the corresponding transcriptional responses of its host. Moreover, the identification of a less-infective Mic1 and a Mic1-resistant host strain provided the evolved genes in the phage-host coevolution during the multiple-generation cultivation in the laboratory. Our findings enrich the knowledge on the interplay and coevolution of M. aeruginosa and its cyanophages and lay the foundation for the future application of cyanophage as a potential eco-friendly and bio-safe agent in controlling the succession of harmful cyanobacterial blooms.},
}

@article {pmid38695111,
year = {2024},
author = {Van Etten, J and Stephens, TG and Chille, E and Lipzen, A and Peterson, D and Barry, K and Grigoriev, IV and Bhattacharya, D},
title = {Diverse fates of ancient horizontal gene transfers in extremophilic red algae.},
journal = {Environmental microbiology},
volume = {26},
number = {5},
pages = {e16629},
doi = {10.1111/1462-2920.16629},
pmid = {38695111},
issn = {1462-2920},
support = {80NSSC19K0462/NASA/NASA/United States ; 80NSSC19K1542/NASA/NASA/United States ; },
mesh = {*Gene Transfer, Horizontal ; *Rhodophyta/genetics ; *Extremophiles/genetics ; *Arsenic/metabolism ; Mercury/metabolism ; Stress, Physiological/genetics ; Inactivation, Metabolic/genetics ; Evolution, Molecular ; },
abstract = {Horizontal genetic transfer (HGT) is a common phenomenon in eukaryotic genomes. However, the mechanisms by which HGT-derived genes persist and integrate into other pathways remain unclear. This topic is of significant interest because, over time, the stressors that initially favoured the fixation of HGT may diminish or disappear. Despite this, the foreign genes may continue to exist if they become part of a broader stress response or other pathways. The conventional model suggests that the acquisition of HGT equates to adaptation. However, this model may evolve into more complex interactions between gene products, a concept we refer to as the 'Integrated HGT Model' (IHM). To explore this concept further, we studied specialized HGT-derived genes that encode heavy metal detoxification functions. The recruitment of these genes into other pathways could provide clear examples of IHM. In our study, we exposed two anciently diverged species of polyextremophilic red algae from the Galdieria genus to arsenic and mercury stress in laboratory cultures. We then analysed the transcriptome data using differential and coexpression analysis. Our findings revealed that mercury detoxification follows a 'one gene-one function' model, resulting in an indivisible response. In contrast, the arsH gene in the arsenite response pathway demonstrated a complex pattern of duplication, divergence and potential neofunctionalization, consistent with the IHM. Our research sheds light on the fate and integration of ancient HGTs, providing a novel perspective on the ecology of extremophiles.},
}

*Gene Transfer, Horizontal
*Rhodophyta/genetics
*Extremophiles/genetics
*Arsenic/metabolism
Mercury/metabolism
Stress, Physiological/genetics
Inactivation, Metabolic/genetics
Evolution, Molecular

@article {pmid38694799,
year = {2024},
author = {Zhang, Y and Xue, G and Wang, F and Zhang, J and Xu, L and Yu, C},
title = {The impact of antibiotic exposure on antibiotic resistance gene dynamics in the gut microbiota of inflammatory bowel disease patients.},
journal = {Frontiers in microbiology},
volume = {15},
number = {},
pages = {1382332},
doi = {10.3389/fmicb.2024.1382332},
pmid = {38694799},
issn = {1664-302X},
abstract = {BACKGROUND: While antibiotics are commonly used to treat inflammatory bowel disease (IBD), their widespread application can disturb the gut microbiota and foster the emergence and spread of antibiotic resistance. However, the dynamic changes to the human gut microbiota and direction of resistance gene transmission under antibiotic effects have not been clearly elucidated.

METHODS: Based on the Human Microbiome Project, a total of 90 fecal samples were collected from 30 IBD patients before, during and after antibiotic treatment. Through the analysis workflow of metagenomics, we described the dynamic process of changes in bacterial communities and resistance genes pre-treatment, during and post-treatment. We explored potential consistent relationships between gut microbiota and resistance genes, and established gene transmission networks among species before and after antibiotic use.

RESULTS: Exposure to antibiotics can induce alterations in the composition of the gut microbiota in IBD patients, particularly a reduction in probiotics, which gradually recovers to a new steady state after cessation of antibiotics. Network analyses revealed intra-phylum transfers of resistance genes, predominantly between taxonomically close organisms. Specific resistance genes showed increased prevalence and inter-species mobility after antibiotic cessation.

CONCLUSION: This study demonstrates that antibiotics shape the gut resistome through selective enrichment and promotion of horizontal gene transfer. The findings provide insights into ecological processes governing resistance gene dynamics and dissemination upon antibiotic perturbation of the microbiota. Optimizing antibiotic usage may help limit unintended consequences like increased resistance in gut bacteria during IBD management.},
}

@article {pmid38694026,
year = {2024},
author = {Reem, A and Almansoob, S and Senan, AM and Kumar Raj, A and Shah, R and Kumar Shrewastwa, M and Kumal, JPP},
title = {Pseudomonas aeruginosa and related antibiotic resistance genes as indicators for wastewater treatment.},
journal = {Heliyon},
volume = {10},
number = {9},
pages = {e29798},
doi = {10.1016/j.heliyon.2024.e29798},
pmid = {38694026},
issn = {2405-8440},
abstract = {This review aims to examine the existence of Pseudomonas aeruginosa (P. aeruginosa) and their antibiotic resistance genes (ARGs) in aquatic settings and the alternative treatment ways. P. aeruginosa in a various aquatic environment have been identified as contaminants with impacts on human health and the environment. P. aeruginosa resistance to multiple antibiotics, such as sulfamethoxazole, ciprofloxacin, quinolone, trimethoprim, tetracycline, vancomycin, as well as specific antibiotic resistance genes including sul1, qnrs, blaVIM, blaTEM, blaCTX, blaAIM-1, tetA, ampC, blaVIM. The development of resistance can occur naturally, through mutations, or via horizontal gene transfer facilitated by sterilizing agents. In addition, an overview of the current knowledge on inactivation of Pseudomonas aeruginosa and ARG and the mechanisms of action of various disinfection processes in water and wastewater (UV chlorine processes, catalytic oxidation, Fenton reaction, and ozonation) is given. An overview of the effects of nanotechnology and the resulting wetlands is also given.},
}

@article {pmid38693917,
year = {2024},
author = {Filgueiras, JPC and Zámocký, M and Turchetto-Zolet, AC},
title = {Unraveling the evolutionary origin of the P5CS gene: a story of gene fusion and horizontal transfer.},
journal = {Frontiers in molecular biosciences},
volume = {11},
number = {},
pages = {1341684},
doi = {10.3389/fmolb.2024.1341684},
pmid = {38693917},
issn = {2296-889X},
abstract = {The accumulation of proline in response to the most diverse types of stress is a widespread defense mechanism. In prokaryotes, fungi, and certain unicellular eukaryotes (green algae), the first two reactions of proline biosynthesis occur through two distinct enzymes, γ-glutamyl kinase (GK E.C. 2.7.2.11) and γ-glutamyl phosphate reductase (GPR E.C. 1.2.1.41), encoded by two different genes, ProB and ProA, respectively. Plants, animals, and a few unicellular eukaryotes carry out these reactions through a single bifunctional enzyme, the Δ[1]-pyrroline-5-carboxylate synthase (P5CS), which has the GK and GPR domains fused. To better understand the origin and diversification of the P5CS gene, we use a robust phylogenetic approach with a broad sampling of the P5CS, ProB and ProA genes, including species from all three domains of life. Our results suggest that the collected P5CS genes have arisen from a single fusion event between the ProA and ProB gene paralogs. A peculiar fusion event occurred in an ancestral eukaryotic lineage and was spread to other lineages through horizontal gene transfer. As for the diversification of this gene family, the phylogeny of the P5CS gene in plants shows that there have been multiple independent processes of duplication and loss of this gene, with the duplications being related to old polyploidy events.},
}

@article {pmid38693486,
year = {2024},
author = {Rork, AM and Bala, AS and Renner, T},
title = {Dynamic evolution of the mTHF gene family associated with primary metabolism across life.},
journal = {BMC genomics},
volume = {25},
number = {1},
pages = {432},
pmid = {38693486},
issn = {1471-2164},
mesh = {*Evolution, Molecular ; *Phylogeny ; *Methylenetetrahydrofolate Dehydrogenase (NADP)/genetics/metabolism ; *Multigene Family ; Archaea/genetics/metabolism ; Eukaryota/genetics/metabolism ; Metabolic Networks and Pathways/genetics ; Gene Transfer, Horizontal ; },
abstract = {BACKGROUND: The folate cycle of one-carbon (C1) metabolism, which plays a central role in the biosynthesis of nucleotides and amino acids, demonstrates the significance of metabolic adaptation. We investigated the evolutionary history of the methylenetetrahydrofolate dehydrogenase (mTHF) gene family, one of the main drivers of the folate cycle, across life.

RESULTS: Through comparative genomic and phylogenetic analyses, we found that several lineages of Archaea lacked domains vital for folate cycle function such as the mTHF catalytic and NAD(P)-binding domains of FolD. Within eukaryotes, the mTHF gene family diversified rapidly. For example, several duplications have been observed in lineages including the Amoebozoa, Opisthokonta, and Viridiplantae. In a common ancestor of Opisthokonta, FolD and FTHFS underwent fusion giving rise to the gene MTHFD1, possessing the domains of both genes.

CONCLUSIONS: Our evolutionary reconstruction of the mTHF gene family associated with a primary metabolic pathway reveals dynamic evolution, including gene birth-and-death, gene fusion, and potential horizontal gene transfer events and/or amino acid convergence.},
}

*Evolution, Molecular
*Phylogeny
*Methylenetetrahydrofolate Dehydrogenase (NADP)/genetics/metabolism
*Multigene Family
Archaea/genetics/metabolism
Eukaryota/genetics/metabolism
Metabolic Networks and Pathways/genetics
Gene Transfer, Horizontal

@article {pmid38692276,
year = {2024},
author = {Li, C and Li, CQ and Chen, ZB and Liu, BQ and Sun, X and Wei, KH and Li, CY and Luan, JB},
title = {Wolbachia symbionts control sex in a parasitoid wasp using a horizontally acquired gene.},
journal = {Current biology : CB},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.cub.2024.04.035},
pmid = {38692276},
issn = {1879-0445},
abstract = {Host reproduction can be manipulated by bacterial symbionts in various ways. Parthenogenesis induction is the most effective type of reproduction manipulation by symbionts for their transmission. Insect sex is determined by regulation of doublesex (dsx) splicing through transformer2 (tra2) and transformer (tra) interaction. Although parthenogenesis induction by symbionts has been studied since the 1970s, its underlying molecular mechanism is unknown. Here we identify a Wolbachia parthenogenesis-induction feminization factor gene (piff) that targets sex-determining genes and causes female-producing parthenogenesis in the haplodiploid parasitoid Encarsia formosa. We found that Wolbachia elimination repressed expression of female-specific dsx and enhanced expression of male-specific dsx, which led to the production of wasp haploid male offspring. Furthermore, we found that E. formosa tra is truncated and non-functional, and Wolbachia has a functional tra homolog, termed piff, with an insect origin. Wolbachia PIFF can colocalize and interact with wasp TRA2. Moreover, Wolbachia piff has coordinated expression with tra2 and dsx of E. formosa. Our results demonstrate the bacterial symbiont Wolbachia has acquired an insect gene to manipulate the host sex determination cascade and induce parthenogenesis in wasps. This study reveals insect-to-bacteria horizontal gene transfer drives the evolution of animal sex determination systems, elucidating a striking mechanism of insect-microbe symbiosis.},
}

@article {pmid38692255,
year = {2024},
author = {Li, H and Wang, Q and Wang, Y and Liu, Y and Zhou, J and Wang, T and Zhu, L and Guo, J},
title = {EDTA enables to alleviate impacts of metal ions on conjugative transfer of antibiotic resistance genes.},
journal = {Water research},
volume = {257},
number = {},
pages = {121659},
doi = {10.1016/j.watres.2024.121659},
pmid = {38692255},
issn = {1879-2448},
abstract = {Various heavy metals are reported to be able to accelerate horizontal transfer of antibiotic resistance genes (ARGs). In real water environmental settings, ubiquitous complexing agents would affect the environmental behaviors of heavy metal ions due to the formation of metal-organic complexes. However, little is known whether the presence of complexing agents would change horizontal gene transfer due to heavy metal exposure. This study aimed to fill this gap by investigating the impacts of a typical complexing agent ethylenediaminetetraacetic acid (EDTA) on the conjugative transfer of plasmid-mediated ARGs induced by a range of heavy metal ions. At the environmentally relevant concentration (0.64 mg L[-1]) of metal ions, all the tested metal ions (Mg[2+], Ca[2+], Co[2+], Pb[2+], Ni[2+], Cu[2+], and Fe[3+]) promoted conjugative transfer of ARGs, while an inhibitory effect was observed at a relatively higher concentration (3.20 mg L[-1]). In contrast, EDTA (0.64 mg L[-1]) alleviated the effects of metal ions on ARGs conjugation transfer, evidenced by 11 %-66 % reduction in the conjugate transfer frequency. Molecular docking and dynamics simulations disclosed that this is attributed to the stronger binding of metal ions with the lipids in cell membranes. Under metal-EDTA exposure, gene expressions related to oxidative stress response, cell membrane permeability, intercellular contact, energy driving force, mobilization, and channels of plasmid transfer were suppressed compared with the metal ions exposure. This study offers insights into the alleviation mechanisms of complexing agents on ARGs transfer induced by free metal ions.},
}

@article {pmid38497713,
year = {2024},
author = {Tang, X-F and Sun, Y-F and Liang, Y-S and Yang, K-Y and Chen, P-T and Li, H-S and Huang, Y-H and Pang, H},
title = {Metabolism, digestion, and horizontal transfer: potential roles and interaction of symbiotic bacteria in the ladybird beetle Novius pumilus and their prey Icerya aegyptiaca.},
journal = {Microbiology spectrum},
volume = {12},
number = {5},
pages = {e0295523},
doi = {10.1128/spectrum.02955-23},
pmid = {38497713},
issn = {2165-0497},
support = {2023YFD1400600//National Key Research and Development Program of China/ ; 32172472//National Natural Science Foundation of China/ ; 31970439//National Natural Science Foundation of China/ ; },
mesh = {Animals ; *Coleoptera/microbiology ; *Symbiosis ; *Bacteria/classification/genetics/metabolism/isolation & purification ; RNA, Ribosomal, 16S/genetics ; Gene Transfer, Horizontal ; Phylogeny ; Female ; Microbiota ; },
abstract = {In this study, we first time sequenced and analyzed the 16S rRNA gene data of predator ladybird beetles Novius pumilus and globally distributed invasive pest Icerya aegyptiaca at different stages, and combined data with bacterial genome sequences in N. pumilus to explored the taxonomic distribution, alpha and beta diversity, differentially abundant bacteria, co-occurrence network, and putative functions of their microbial community. Our finding revealed that Candidatus Walczuchella, which exhibited a higher abundance in I. aegyptiaca, possessed several genes in essential amino acid biosynthesis and seemed to perform roles in providing nutrients to the host, similar to other obligate symbionts in scale insects. Lactococcus, Serratia, and Pseudomonas, more abundant in N. pumilus, were predicted to have genes related to hydrocarbon, fatty acids, and chitin degradation, which may assist their hosts in digesting the wax shell covering the scale insects. Notably, our result showed that Lactococcus had relatively higher abundances in adults and eggs compared to other stages in N. pumilus, indicating potential vertical transmission. Additionally, we found that Arsenophonus, known to influence sex ratios in whitefly and wasp, may also function in I. aegyptiaca, probably by influencing nutrient metabolism as it similarly had many genes corresponding to vitamin B and essential amino acid biosynthesis. Also, we observed a potential horizontal transfer of Arsenophonus between the scale insect and its predator, with a relatively high abundance in the ladybirds compared to other bacteria from the scale insects.IMPORTANCEThe composition and dynamic changes of microbiome in different developmental stages of ladybird beetles Novius pumilus with its prey Icerya aegyptiaca were detected. We found that Candidatus Walczuchella, abundant in I. aegyptiaca, probably provide nutrients to their host based on their amino acid biosynthesis-related genes. Abundant symbionts in N. pumilus, including Lactococcus, Serratia, and Pseudophonus, may help the host digest the scale insects with their hydrocarbon, fatty acid, and chitin degrading-related genes. A key endosymbiont Arsenophonus may play potential roles in the nutrient metabolisms and sex determination in I. aegyptiaca, and is possibly transferred from the scale insect to the predator.},
}

Animals
*Coleoptera/microbiology
*Symbiosis
*Bacteria/classification/genetics/metabolism/isolation & purification
RNA, Ribosomal, 16S/genetics
Gene Transfer, Horizontal
Phylogeny
Female
Microbiota

@article {pmid38692150,
year = {2024},
author = {Cai, Y and Chen, C and Sun, T and Li, G and Wang, W and Zhao, H and An, T},
title = {Mariculture waters as yet another hotbed for the creation and transfer of new antibiotic-resistant pathogenome.},
journal = {Environment international},
volume = {187},
number = {},
pages = {108704},
doi = {10.1016/j.envint.2024.108704},
pmid = {38692150},
issn = {1873-6750},
abstract = {With the rapid growth of aquaculture globally, large amounts of antibiotics have been used to treat aquatic disease, which may accelerate induction and spread of antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARGs) in aquaculture environments. Herein, metagenomic and 16S rRNA analyses were used to analyze the potentials and co-occurrence patterns of pathogenome (culturable and unculturable pathogens), antibiotic resistome (ARGs), and mobilome (mobile genetic elements (MGEs)) from mariculture waters near 5000 km coast of South China. Total 207 species of pathogens were identified, with only 10 culturable species. Furthermore, more pathogen species were detected in mariculture waters than those in coastal waters, and mariculture waters were prone to become reservoirs of unculturable pathogens. In addition, 913 subtypes of 21 ARG types were also identified, with multidrug resistance genes as the majority. MGEs including plasmids, integrons, transposons, and insertion sequences were abundantly present in mariculture waters. The co-occurrence network pattern between pathogenome, antibiotic resistome, and mobilome suggested that most of pathogens may be potential multidrug resistant hosts, possibly due to high frequency of horizontal gene transfer. These findings increase our understanding of mariculture waters as reservoirs of antibiotic resistome and mobilome, and as yet another hotbed for creation and transfer of new antibiotic-resistant pathogenome.},
}

@article {pmid38689039,
year = {2024},
author = {Shepherd, MJ and Fu, T and Harrington, NE and Kottara, A and Cagney, K and Chalmers, JD and Paterson, S and Fothergill, JL and Brockhurst, MA},
title = {Ecological and evolutionary mechanisms driving within-patient emergence of antimicrobial resistance.},
journal = {Nature reviews. Microbiology},
volume = {},
number = {},
pages = {},
pmid = {38689039},
issn = {1740-1534},
abstract = {The ecological and evolutionary mechanisms of antimicrobial resistance (AMR) emergence within patients and how these vary across bacterial infections are poorly understood. Increasingly widespread use of pathogen genome sequencing in the clinic enables a deeper understanding of these processes. In this Review, we explore the clinical evidence to support four major mechanisms of within-patient AMR emergence in bacteria: spontaneous resistance mutations; in situ horizontal gene transfer of resistance genes; selection of pre-existing resistance; and immigration of resistant lineages. Within-patient AMR emergence occurs across a wide range of host niches and bacterial species, but the importance of each mechanism varies between bacterial species and infection sites within the body. We identify potential drivers of such differences and discuss how ecological and evolutionary analysis could be embedded within clinical trials of antimicrobials, which are powerful but underused tools for understanding why these mechanisms vary between pathogens, infections and individuals. Ultimately, improving understanding of how host niche, bacterial species and antibiotic mode of action combine to govern the ecological and evolutionary mechanism of AMR emergence in patients will enable more predictive and personalized diagnosis and antimicrobial therapies.},
}

@article {pmid38688912,
year = {2024},
author = {Yang, QE and Ma, X and Li, M and Zhao, M and Zeng, L and He, M and Deng, H and Liao, H and Rensing, C and Friman, VP and Zhou, S and Walsh, TR},
title = {Evolution of triclosan resistance modulates bacterial permissiveness to multidrug resistance plasmids and phages.},
journal = {Nature communications},
volume = {15},
number = {1},
pages = {3654},
pmid = {38688912},
issn = {2041-1723},
support = {32100150//National Natural Science Foundation of China (National Science Foundation of China)/ ; 42277436//National Natural Science Foundation of China (National Science Foundation of China)/ ; },
mesh = {*Triclosan/pharmacology ; *Plasmids/genetics ; *Klebsiella pneumoniae/drug effects/genetics/virology ; *Bacteriophages/genetics/physiology ; Drug Resistance, Multiple, Bacterial/genetics ; Mutation ; Gene Transfer, Horizontal ; Whole Genome Sequencing ; Evolution, Molecular ; Anti-Bacterial Agents/pharmacology ; },
abstract = {The horizontal transfer of plasmids has been recognized as one of the key drivers for the worldwide spread of antimicrobial resistance (AMR) across bacterial pathogens. However, knowledge remain limited about the contribution made by environmental stress on the evolution of bacterial AMR by modulating horizontal acquisition of AMR plasmids and other mobile genetic elements. Here we combined experimental evolution, whole genome sequencing, reverse genetic engineering, and transcriptomics to examine if the evolution of chromosomal AMR to triclosan (TCS) disinfectant has correlated effects on modulating bacterial pathogen (Klebsiella pneumoniae) permissiveness to AMR plasmids and phage susceptibility. Herein, we show that TCS exposure increases the evolvability of K. pneumoniae to evolve TCS-resistant mutants (TRMs) by acquiring mutations and altered expression of several genes previously associated with TCS and antibiotic resistance. Notably, nsrR deletion increases conjugation permissiveness of K. pneumoniae to four AMR plasmids, and enhances susceptibility to various Klebsiella-specific phages through the downregulation of several bacterial defense systems and changes in membrane potential with altered reactive oxygen species response. Our findings suggest that unrestricted use of TCS disinfectant imposes a dual impact on bacterial antibiotic resistance by augmenting both chromosomally and horizontally acquired AMR mechanisms.},
}

*Triclosan/pharmacology
*Plasmids/genetics
*Klebsiella pneumoniae/drug effects/genetics/virology
*Bacteriophages/genetics/physiology
Drug Resistance, Multiple, Bacterial/genetics
Mutation
Gene Transfer, Horizontal
Whole Genome Sequencing
Evolution, Molecular
Anti-Bacterial Agents/pharmacology

@article {pmid38688811,
year = {2024},
author = {Szczepankowska, AK and Łobocka, M},
title = {Exploring the role of phage plasmids in gene transfers.},
journal = {Trends in genetics : TIG},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.tig.2024.04.011},
pmid = {38688811},
issn = {0168-9525},
abstract = {Bacteriophages and plasmids drive horizontal gene transfer (HGT) in bacteria. Phage-plasmids (P-Ps) are hybrids of plasmid and phages. Pfeifer and Rocha recently demonstrated that P-Ps can serve as intermediates in gene exchanges between these two types of elements, identified categories of preferentially transferred genes, and reconstructed gene flows involving phage P1-like P-Ps.},
}

@article {pmid38683832,
year = {2024},
author = {Guillén-Chable, F and Valdez Iuit, JO and Avila Castro, LA and Rosas, C and Merino, E and Rodríguez-Escamilla, Z and Martínez-Núñez, MA},
title = {Geographical distribution of mobile genetic elements in microbial communities along the Yucatan coast.},
journal = {PloS one},
volume = {19},
number = {4},
pages = {e0301642},
doi = {10.1371/journal.pone.0301642},
pmid = {38683832},
issn = {1932-6203},
mesh = {*Interspersed Repetitive Sequences/genetics ; *Gene Transfer, Horizontal ; *Microbiota/genetics ; Mexico ; Bacteria/genetics/classification ; Proteobacteria/genetics ; },
abstract = {Horizontal gene transfer (HGT) is a well-documented strategy used by bacteria to enhance their adaptability to challenging environmental conditions. Through HGT, a group of conserved genetic elements known as mobile genetic elements (MGEs) is disseminated within bacterial communities. MGEs offer numerous advantages to the host, increasing its fitness by acquiring new functions that help bacteria contend with adverse conditions, including exposure to heavy metal and antibiotics. This study explores MGEs within microbial communities along the Yucatan coast using a metatranscriptomics approach. Prior to this research, nothing was known about the coastal Yucatan's microbial environmental mobilome and HGT processes between these bacterial communities. This study reveals a positive correlation between MGEs and antibiotic resistance genes (ARGs) along the Yucatan coast, with higher MGEs abundance in more contaminated sites. The Proteobacteria and Firmicutes groups exhibited the highest number of MGEs. It's important to highlight that the most abundant classes of MGEs might not be the ones most strongly linked to ARGs, as observed for the recombination/repair class. This work presents the first geographical distribution of the environmental mobilome in Yucatan Peninsula mangroves.},
}

*Interspersed Repetitive Sequences/genetics
*Gene Transfer, Horizontal
*Microbiota/genetics
Mexico
Bacteria/genetics/classification
Proteobacteria/genetics

@article {pmid38683670,
year = {2024},
author = {Ferrari, E and Di Benedetto, G and Firrincieli, A and Presentato, A and Frascari, D and Cappelletti, M},
title = {Unravelling the role of the group 6 soluble di-iron monooxygenase (SDIMO) SmoABCD in alkane metabolism and chlorinated alkane degradation.},
journal = {Microbial biotechnology},
volume = {17},
number = {5},
pages = {e14453},
pmid = {38683670},
issn = {1751-7915},
mesh = {*Alkanes/metabolism ; *Mixed Function Oxygenases/metabolism/genetics ; Genetic Complementation Test ; Mutagenesis, Insertional ; Biotransformation ; DNA Transposable Elements ; Hydrocarbons, Chlorinated/metabolism ; },
abstract = {Soluble di-iron monooxygenases (SDIMOs) are multi-component enzymes catalysing the oxidation of various substrates. These enzymes are characterized by high sequence and functional diversity that is still not well understood despite their key role in biotechnological processes including contaminant biodegradation. In this study, we analysed a mutant of Rhodoccocus aetherivorans BCP1 (BCP1-2.10) characterized by a transposon insertion in the gene smoA encoding the alpha subunit of the plasmid-located SDIMO SmoABCD. The mutant BCP1-2.10 showed a reduced capacity to grow on propane, lost the ability to grow on butane, pentane and n-hexane and was heavily impaired in the capacity to degrade chloroform and trichloroethane. The expression of the additional SDIMO prmABCD in BCP1-2.10 probably allowed the mutant to partially grow on propane and to degrade it, to some extent, together with the other short-chain n-alkanes. The complementation of the mutant, conducted by introducing smoABCD in the genome as a single copy under a constitutive promoter or within a plasmid under a thiostreptone-inducible promoter, allowed the recovery of the alkanotrophic phenotype as well as the capacity to degrade chlorinated n-alkanes. The heterologous expression of smoABCD allowed a non-alkanotrophic Rhodococcus strain to grow on pentane and n-hexane when the gene cluster was introduced together with the downstream genes encoding alcohol and aldehyde dehydrogenases and a GroEL chaperon. BCP1 smoA gene was shown to belong to the group 6 SDIMOs, which is a rare group of monooxygenases mostly present in Mycobacterium genus and in a few Rhodococcus strains. SmoABCD originally evolved in Mycobacterium and was then acquired by Rhodococcus through horizontal gene transfer events. This work extends the knowledge of the biotechnologically relevant SDIMOs by providing functional and evolutionary insights into a group 6 SDIMO in Rhodococcus and demonstrating its key role in the metabolism of short-chain alkanes and degradation of chlorinated n-alkanes.},
}

*Alkanes/metabolism
*Mixed Function Oxygenases/metabolism/genetics
Genetic Complementation Test
Mutagenesis, Insertional
Biotransformation
DNA Transposable Elements
Hydrocarbons, Chlorinated/metabolism

@article {pmid38683013,
year = {2024},
author = {Taylor, AJ and Yahara, K and Pascoe, B and Ko, S and Mageiros, L and Mourkas, E and Calland, JK and Puranen, S and Hitchings, MD and Jolley, KA and Kobras, CM and Bayliss, S and Williams, NJ and van Vliet, AHM and Parkhill, J and Maiden, MCJ and Corander, J and Hurst, LD and Falush, D and Keim, P and Didelot, X and Kelly, DJ and Sheppard, SK},
title = {Epistasis, core-genome disharmony, and adaptation in recombining bacteria.},
journal = {mBio},
volume = {},
number = {},
pages = {e0058124},
doi = {10.1128/mbio.00581-24},
pmid = {38683013},
issn = {2150-7511},
abstract = {Recombination of short DNA fragments via horizontal gene transfer (HGT) can introduce beneficial alleles, create genomic disharmony through negative epistasis, and create adaptive gene combinations through positive epistasis. For non-core (accessory) genes, the negative epistatic cost is likely to be minimal because the incoming genes have not co-evolved with the recipient genome and are frequently observed as tightly linked cassettes with major effects. By contrast, interspecific recombination in the core genome is expected to be rare because disruptive allelic replacement is likely to introduce negative epistasis. Why then is homologous recombination common in the core of bacterial genomes? To understand this enigma, we take advantage of an exceptional model system, the common enteric pathogens Campylobacter jejuni and C. coli that are known for very high magnitude interspecies gene flow in the core genome. As expected, HGT does indeed disrupt co-adapted allele pairings, indirect evidence of negative epistasis. However, multiple HGT events enable recovery of the genome's co-adaption between introgressing alleles, even in core metabolism genes (e.g., formate dehydrogenase). These findings demonstrate that, even for complex traits, genetic coalitions can be decoupled, transferred, and independently reinstated in a new genetic background-facilitating transition between fitness peaks. In this example, the two-step recombinational process is associated with C. coli that are adapted to the agricultural niche.IMPORTANCEGenetic exchange among bacteria shapes the microbial world. From the acquisition of antimicrobial resistance genes to fundamental questions about the nature of bacterial species, this powerful evolutionary force has preoccupied scientists for decades. However, the mixing of genes between species rests on a paradox: 0n one hand, promoting adaptation by conferring novel functionality; on the other, potentially introducing disharmonious gene combinations (negative epistasis) that will be selected against. Taking an interdisciplinary approach to analyze natural populations of the enteric bacteria Campylobacter, an ideal example of long-range admixture, we demonstrate that genes can independently transfer across species boundaries and rejoin in functional networks in a recipient genome. The positive impact of two-gene interactions appears to be adaptive by expanding metabolic capacity and facilitating niche shifts through interspecific hybridization. This challenges conventional ideas and highlights the possibility of multiple-step evolution of multi-gene traits by interspecific introgression.},
}

@article {pmid38537404,
year = {2024},
author = {Cui, J and Dong, Y and Chen, Q and Zhang, C and He, K and Hu, G and He, D and Yuan, L},
title = {Horizontal transfer characterization of ColV plasmids in blaCTX-M-bearing avian Escherichia coli.},
journal = {Poultry science},
volume = {103},
number = {5},
pages = {103631},
doi = {10.1016/j.psj.2024.103631},
pmid = {38537404},
issn = {1525-3171},
mesh = {*Escherichia coli/genetics/drug effects ; Animals ; *Escherichia coli Infections/veterinary/microbiology ; *Gene Transfer, Horizontal ; *Poultry Diseases/microbiology ; *Plasmids/genetics ; *Chickens ; *beta-Lactamases/genetics/metabolism ; Drug Resistance, Multiple, Bacterial/genetics ; Anti-Bacterial Agents/pharmacology ; },
abstract = {Extended-spectrum-β-lactamases (ESBLs)-producing Escherichia coli conferred resistance to most β-lactams, except for carbapenems. To date, the transmission mechanism of blaCTX-M, as the most common ESBLs subtype, in E. coli has received sustained attention around the worldwide, but the research on the pathogenicity of blaCTX-M-bearing E. coli is still scarce. The aims of this study were to discern the spread characteristics of ColV (encoding colicin V) plasmids in blaCTX-M-positive E. coli. The multi-drug resistance traits, phylogroups, and ColV plasmid profilings were screened in 76 blaCTX-M-positive E. coli. Thereafter, the genetic profiles of E. coli G12 and GZM7 were determined by whole genome sequencing, conjugation and S1-pulsed-field gel electrophoresis. The median lethal dose was analyzed in E. coli G12 and TG12A, the ColV-plasmid transconjugant of G12. Of all 76 blaCTX-M-bearing E. coli, 67.11% exhibited resistance to at least 2 drugs in addition to ceftiofur, 14.47% carried ColV-positive plasmids, and 53.95% were phylogroup C. Further studies demonstrated that the blaCTX-M-bearing E. coli G12 was assigned to the predominant lineage O78:H4-ST117 of phylogroup G. In addition, its ColV-positive plasmid simultaneously carried multiple resistance genes, and could be independently transferred to confer partial pathogenicity on its host by plasmid mating. E. coli GZM7 was O53:H9-ST23 of phylogroup C, which belonged to another representative lineage of APEC (avian pathogenic E. coli). Its ColV-positive plasmid could complete conjugation with the help of the other coexisting-resistance conjugative plasmid, although it failed to transfer alone. Our findings highlight the flexibly horizontal transfer of ColV plasmids along with multidrug-resistant genes among blaCTX-M-bearing E. coli poses a threat to poultry health and food safety, which contributes to elucidate the concept of "One Health" and deserves particular concern.},
}

*Escherichia coli/genetics/drug effects
Animals
*Escherichia coli Infections/veterinary/microbiology
*Gene Transfer, Horizontal
*Poultry Diseases/microbiology
*Plasmids/genetics
*Chickens
*beta-Lactamases/genetics/metabolism
Drug Resistance, Multiple, Bacterial/genetics
Anti-Bacterial Agents/pharmacology

@article {pmid38508537,
year = {2024},
author = {Yang, W and Tang, C and Shen, S and Shi, Q and Hu, F},
title = {Spread and evolution of blaKPC-plasmid between Serratia marcescens and Klebsiella pneumoniae.},
journal = {International journal of antimicrobial agents},
volume = {63},
number = {5},
pages = {107149},
doi = {10.1016/j.ijantimicag.2024.107149},
pmid = {38508537},
issn = {1872-7913},
mesh = {*Serratia marcescens/genetics/drug effects/isolation & purification/enzymology ; *Klebsiella pneumoniae/genetics/drug effects ; Humans ; *Plasmids/genetics ; *Microbial Sensitivity Tests ; *beta-Lactamases/genetics ; *Serratia Infections/microbiology/epidemiology ; *Anti-Bacterial Agents/pharmacology ; *Klebsiella Infections/microbiology/epidemiology ; *Whole Genome Sequencing ; Ceftazidime/pharmacology ; Drug Combinations ; Drug Resistance, Multiple, Bacterial/genetics ; Azabicyclo Compounds/pharmacology ; Sputum/microbiology ; Evolution, Molecular ; Gene Transfer, Horizontal ; Carbapenems/pharmacology ; },
abstract = {OBJECTIVES: blaKPC-carrying Enterobacterales have post great challenges to global healthcare systems. In this study, we reported the evolution and spread of blaKPC between Serratia marcescens and Klebsiella pneumoniae.

METHODS: Four S. marcescens and one K. pneumoniae strains were isolated from the sputum samples of the patient. Antimicrobial susceptibility tests and whole genome sequencing were performed to investigate the phenotype & genotype of strains. Conjugation assays, cloning experiment and kinetic parameters measuring were performed to explore the spread and antimicrobial resistance mechanisms.

RESULTS: The evolution and transmission of blaKPC-2 occurred during the treatment of ceftazidime-avibactam and trimethoprim-sulfamethoxazole. Analysis of the antimicrobial susceptibility and genetic profiles of the clinical strains showed that blaKPC-2 evolved into blaKPC-71 and blaKPC-44, together with resistance to ceftazidime-avibactam and carbapenems susceptibility recovery under antimicrobial pressure. Cloning and expression of blaKPC-44 & blaKPC-71 in E. coli DH5α showed that KPC-44 and KPC-71 resulted in a 64∼128-fold increase in the MIC value for ceftazidime-avibactam. Meanwhile, the kinetic assays also showed that the enzyme activity of KPC-44 and KPC-71 towards carbapenems was destroyed and couldn't be inhibited by avibactam. Based on the conjugation assay and whole genome sequence analyses, we provided evolutionary insights into the transmission pathway trace of blaKPC-bearing plasmids between S. marcescens and K. pneumoniae.

CONCLUSIONS: Mixed-species co-infection is one of the risk factors leading to the spread of plasmids carrying carbapenem-resistant genes, and increased surveillance of multidrug-resistant Enterobacterales is urgently needed.},
}

*Serratia marcescens/genetics/drug effects/isolation & purification/enzymology
*Klebsiella pneumoniae/genetics/drug effects
Humans
*Plasmids/genetics
*Microbial Sensitivity Tests
*beta-Lactamases/genetics
*Serratia Infections/microbiology/epidemiology
*Anti-Bacterial Agents/pharmacology
*Klebsiella Infections/microbiology/epidemiology
*Whole Genome Sequencing
Ceftazidime/pharmacology
Drug Combinations
Drug Resistance, Multiple, Bacterial/genetics
Azabicyclo Compounds/pharmacology
Sputum/microbiology
Evolution, Molecular
Gene Transfer, Horizontal
Carbapenems/pharmacology

@article {pmid38682189,
year = {2024},
author = {Almatroudi, A},
title = {Investigating Biofilms: Advanced Methods for Comprehending Microbial Behavior and Antibiotic Resistance.},
journal = {Frontiers in bioscience (Landmark edition)},
volume = {29},
number = {4},
pages = {133},
doi = {10.31083/j.fbl2904133},
pmid = {38682189},
issn = {2768-6698},
mesh = {*Biofilms/drug effects/growth & development ; Humans ; Drug Resistance, Microbial/genetics ; Anti-Bacterial Agents/pharmacology ; Gene Transfer, Horizontal ; Drug Resistance, Bacterial/genetics ; Extracellular Polymeric Substance Matrix/metabolism ; Bacteria/genetics/drug effects/metabolism ; },
abstract = {Biofilms, which consist of microorganisms enclosed in an extracellular polymeric material (EPS), hold immense importance in the fields of environmental research, industry, and medicine. They play a significant role in ecosystem dynamics and stability, but they also pose issues such as biofouling, corrosion, and pollution. Biofilms in medical environments are linked to persistent infections and elevated healthcare expenses. The EPS matrix plays a crucial role in maintaining the structural integrity and antibiotic resistance of these structures. The research primarily investigates the role of the EPS matrix in facilitating horizontal gene transfer among biofilm communities, with a particular emphasis on EPS and its impact on this process. The process is recognized as a pivotal mechanism in the emergence of antibiotic resistance, underscoring the crucial function of EPS in the dynamics of biofilms. The analysis also highlights the significant financial constraints caused by biofilms in several industries. Biofilm-associated infections in the healthcare sector result in escalated treatment expenses and extended hospitalization periods. In an industrial context, biofilms have a role in increasing maintenance expenses and product contamination, emphasizing the need for efficient management solutions. This review presents the most recent progress in biofilm research, emphasizing the utilization of sophisticated imaging tools and molecular methodologies. In addition to conventional imaging techniques, the research explores the utilization of sophisticated molecular tools, such as DNA and RNA sequencing, in conjunction with proteomics. These approaches are essential for assessing the genetic and metabolic mechanisms that regulate biofilm development and antibiotic resistance. The review underscores the significance of employing an interdisciplinary methodology in the study of biofilms. By incorporating a range of approaches, such as sophisticated imaging and molecular analysis, a comprehensive understanding of biofilm dynamics may be achieved. This approach also opens up possibilities for developing novel solutions to address the negative impacts of biofilms on health, industry, and the environment.},
}

*Biofilms/drug effects/growth & development
Humans
Drug Resistance, Microbial/genetics
Anti-Bacterial Agents/pharmacology
Gene Transfer, Horizontal
Drug Resistance, Bacterial/genetics
Extracellular Polymeric Substance Matrix/metabolism
Bacteria/genetics/drug effects/metabolism

@article {pmid38678226,
year = {2024},
author = {Alexa, EA and Cobo-Díaz, JF and Renes, E and O Callaghan, TF and Kilcawley, K and Mannion, D and Skibinska, I and Ruiz, L and Margolles, A and Fernández-Gómez, P and Alvarez-Molina, A and Puente-Gómez, P and Crispie, F and López, M and Prieto, M and Cotter, PD and Alvarez-Ordóñez, A},
title = {The detailed analysis of the microbiome and resistome of artisanal blue-veined cheeses provides evidence on sources and patterns of succession linked with quality and safety traits.},
journal = {Microbiome},
volume = {12},
number = {1},
pages = {78},
pmid = {38678226},
issn = {2049-2618},
support = {818368//European Commission under the European Union´s Horizon 2020 research and innovation program/ ; 818368//European Commission under the European Union´s Horizon 2020 research and innovation program/ ; 818368//European Commission under the European Union´s Horizon 2020 research and innovation program/ ; 818368//European Commission under the European Union´s Horizon 2020 research and innovation program/ ; 818368//European Commission under the European Union´s Horizon 2020 research and innovation program/ ; AGL2016-78085-P//Ministry of Science and Innovation of the Spanish Government/ ; AGL2016-78085-P//Ministry of Science and Innovation of the Spanish Government/ ; AGL2016-78085-P//Ministry of Science and Innovation of the Spanish Government/ ; },
mesh = {*Cheese/microbiology ; *Microbiota/genetics ; *Food Microbiology ; Bacteria/classification/genetics ; Caves/microbiology ; Corynebacterium/genetics ; Longitudinal Studies ; Metagenome ; Lactococcus/genetics/classification ; RNA, Ribosomal, 16S/genetics ; Staphylococcus/genetics/classification ; Food Safety ; },
abstract = {BACKGROUND: Artisanal cheeses usually contain a highly diverse microbial community which can significantly impact their quality and safety. Here, we describe a detailed longitudinal study assessing the impact of ripening in three natural caves on the microbiome and resistome succession across three different producers of Cabrales blue-veined cheese.

RESULTS: Both the producer and cave in which cheeses were ripened significantly influenced the cheese microbiome. Lactococcus and the former Lactobacillus genus, among other taxa, showed high abundance in cheeses at initial stages of ripening, either coming from the raw material, starter culture used, and/or the environment of processing plants. Along cheese ripening in caves, these taxa were displaced by other bacteria, such as Tetragenococcus, Corynebacterium, Brevibacterium, Yaniella, and Staphylococcus, predominantly originating from cave environments (mainly food contact surfaces), as demonstrated by source-tracking analysis, strain analysis at read level, and the characterization of 613 metagenome-assembled genomes. The high abundance of Tetragenococcus koreensis and Tetragenococcus halophilus detected in cheese has not been found previously in cheese metagenomes. Furthermore, Tetragenococcus showed a high level of horizontal gene transfer with other members of the cheese microbiome, mainly with Lactococcus and Staphylococcus, involving genes related to carbohydrate metabolism functions. The resistome analysis revealed that raw milk and the associated processing environments are a rich reservoir of antimicrobial resistance determinants, mainly associated with resistance to aminoglycosides, tetracyclines, and β-lactam antibiotics and harbored by aerobic gram-negative bacteria of high relevance from a safety point of view, such as Escherichia coli, Salmonella enterica, Acinetobacter, and Klebsiella pneumoniae, and that the displacement of most raw milk-associated taxa by cave-associated taxa during ripening gave rise to a significant decrease in the load of ARGs and, therefore, to a safer end product.

CONCLUSION: Overall, the cave environments represented an important source of non-starter microorganisms which may play a relevant role in the quality and safety of the end products. Among them, we have identified novel taxa and taxa not previously regarded as being dominant components of the cheese microbiome (Tetragenococcus spp.), providing very valuable information for the authentication of this protected designation of origin artisanal cheese. Video Abstract.},
}

*Cheese/microbiology
*Microbiota/genetics
*Food Microbiology
Bacteria/classification/genetics
Caves/microbiology
Corynebacterium/genetics
Longitudinal Studies
Metagenome
Lactococcus/genetics/classification
RNA, Ribosomal, 16S/genetics
Staphylococcus/genetics/classification
Food Safety

@article {pmid38678007,
year = {2024},
author = {Wang, X and Tang, Y and Yue, X and Wang, S and Yang, K and Xu, Y and Shen, Q and Friman, VP and Wei, Z},
title = {The role of rhizosphere phages in soil health.},
journal = {FEMS microbiology ecology},
volume = {},
number = {},
pages = {},
doi = {10.1093/femsec/fiae052},
pmid = {38678007},
issn = {1574-6941},
abstract = {While the One Health framework has emphasized the importance of soil microbiomes for plant and human health, one of the most diverse and abundant groups-bacterial viruses, i.e. phages-has been mostly neglected. This perspective reviews the significance of phages for plant health in rhizosphere and explores their ecological and evolutionary impacts on soil ecosystems. We first summarize our current understanding of the diversity and ecological roles of phages in soil microbiomes in terms of nutrient cycling, top-down density regulation and pathogen suppression. We then consider how phages drive bacterial evolution in soils by promoting horizontal gene transfer, encoding auxiliary metabolic genes that increase host bacterial fitness and selecting for phage-resistant mutants with altered ecology due to trade-offs with pathogen competitiveness and virulence. Finally, we consider challenges and avenues for phage research in soil ecosystems and how to elucidate the significance of phages for microbial ecology and evolution and soil ecosystem functioning in the future. We conclude that similar to bacteria, phages likely play important roles in connecting different One Health compartments, affecting microbiome diversity and functions in soils. From the applied perspective, phages could offer novel approaches to modulate and optimize microbial and microbe-plant interactions to enhance soil health.},
}

@article {pmid38669903,
year = {2024},
author = {Liu, H and Al-Dhabi, NA and Jiang, H and Liu, B and Qing, T and Feng, B and Ma, T and Tang, W and Zhang, P},
title = {Toward nitrogen recovery: Co-cultivation of microalgae and bacteria enhances the production of high-value nitrogen-rich cyanophycin.},
journal = {Water research},
volume = {256},
number = {},
pages = {121624},
doi = {10.1016/j.watres.2024.121624},
pmid = {38669903},
issn = {1879-2448},
abstract = {The algal-bacterial wastewater treatment process has been proven to be highly efficient in removing nutrients and recovering nitrogen (N). However, the recovery of the valuable N-rich biopolymer, cyanophycin, remains limited. This research explored the synthesis mechanism and recovery potential of cyanophycin within two algal-bacterial symbiotic reactors. The findings reveal that the synergy between algae and bacteria enhances the removal of N and phosphorus. The crude contents of cyanophycin in the algal-bacterial consortia reached 115 and 124 mg/g of mixed liquor suspended solids (MLSS), respectively, showing an increase of 11.7 %-20.4 % (p < 0.001) compared with conventional activated sludge. Among the 170 metagenome-assembled genomes (MAGs) analyzed, 50 were capable of synthesizing cyanophycin, indicating that cyanophycin producers are common in algal-bacterial systems. The compositions of cyanophycin producers in the two algal-bacterial reactors were affected by different lighting initiation time. The study identified two intracellular synthesis pathways for cyanophycin. Approximately 36 MAGs can synthesize cyanophycin de novo using ammonium and glucose, while the remaining 14 MAGs require exogenous arginine for production. Notably, several MAGs with high abundance are capable of assimilating both nitrate and ammonium into cyanophycin, demonstrating a robust N utilization capability. This research also marks the first identification of potential horizontal gene transfer of the cyanophycin synthase encoding gene (cphA) within the wastewater microbial community. This suggests that the spread of cphA could expand the population of cyanophycin producers. The study offers new insights into recycling the high-value N-rich biopolymer cyanophycin, contributing to the advancement of wastewater resource utilization.},
}

@article {pmid38664322,
year = {2024},
author = {Vincent, J and Tenore, A and Mattei, MR and Frunzo, L},
title = {Modelling Plasmid-Mediated Horizontal Gene Transfer in Biofilms.},
journal = {Bulletin of mathematical biology},
volume = {86},
number = {6},
pages = {63},
pmid = {38664322},
issn = {1522-9602},
support = {861088//H2020 Marie Skłodowska-Curie Actions/ ; },
mesh = {*Biofilms/growth & development ; *Gene Transfer, Horizontal ; *Plasmids/genetics ; *Mathematical Concepts ; *Models, Biological ; *Models, Genetic ; Conjugation, Genetic ; Anti-Bacterial Agents/pharmacology ; },
abstract = {In this study, we present a mathematical model for plasmid spread in a growing biofilm, formulated as a nonlocal system of partial differential equations in a 1-D free boundary domain. Plasmids are mobile genetic elements able to transfer to different phylotypes, posing a global health problem when they carry antibiotic resistance factors. We model gene transfer regulation influenced by nearby potential receptors to account for recipient-sensing. We also introduce a promotion function to account for trace metal effects on conjugation, based on literature data. The model qualitatively matches experimental results, showing that contaminants like toxic metals and antibiotics promote plasmid persistence by favoring plasmid carriers and stimulating conjugation. Even at higher contaminant concentrations inhibiting conjugation, plasmid spread persists by strongly inhibiting plasmid-free cells. The model also replicates higher plasmid density in biofilm's most active regions.},
}

*Biofilms/growth & development
*Gene Transfer, Horizontal
*Plasmids/genetics
*Mathematical Concepts
*Models, Biological
*Models, Genetic
Conjugation, Genetic
Anti-Bacterial Agents/pharmacology

@article {pmid38658529,
year = {2024},
author = {Xie, O and Zachreson, C and Tonkin-Hill, G and Price, DJ and Lacey, JA and Morris, JM and McDonald, MI and Bowen, AC and Giffard, PM and Currie, BJ and Carapetis, JR and Holt, DC and Bentley, SD and Davies, MR and Tong, SYC},
title = {Overlapping Streptococcus pyogenes and Streptococcus dysgalactiae subspecies equisimilis household transmission and mobile genetic element exchange.},
journal = {Nature communications},
volume = {15},
number = {1},
pages = {3477},
pmid = {38658529},
issn = {2041-1723},
support = {/WT_/Wellcome Trust/United Kingdom ; 206194/WT_/Wellcome Trust/United Kingdom ; },
mesh = {*Streptococcus pyogenes/genetics/isolation & purification/classification ; *Streptococcal Infections/transmission/microbiology ; Humans ; *Streptococcus/genetics/isolation & purification ; *Interspersed Repetitive Sequences/genetics ; *Gene Transfer, Horizontal ; Australia ; Genome, Bacterial/genetics ; Female ; Male ; Child ; Family Characteristics ; Adult ; Child, Preschool ; Adolescent ; Longitudinal Studies ; Drug Resistance, Bacterial/genetics ; Young Adult ; },
abstract = {Streptococcus dysgalactiae subspecies equisimilis (SDSE) and Streptococcus pyogenes share skin and throat niches with extensive genomic homology and horizontal gene transfer (HGT) possibly underlying shared disease phenotypes. It is unknown if cross-species transmission interaction occurs. Here, we conduct a genomic analysis of a longitudinal household survey in remote Australian First Nations communities for patterns of cross-species transmission interaction and HGT. Collected from 4547 person-consultations, we analyse 294 SDSE and 315 S. pyogenes genomes. We find SDSE and S. pyogenes transmission intersects extensively among households and show that patterns of co-occurrence and transmission links are consistent with independent transmission without inter-species interference. We identify at least one of three near-identical cross-species mobile genetic elements (MGEs) carrying antimicrobial resistance or streptodornase virulence genes in 55 (19%) SDSE and 23 (7%) S. pyogenes isolates. These findings demonstrate co-circulation of both pathogens and HGT in communities with a high burden of streptococcal disease, supporting a need to integrate SDSE and S. pyogenes surveillance and control efforts.},
}

*Streptococcus pyogenes/genetics/isolation & purification/classification
*Streptococcal Infections/transmission/microbiology
Humans
*Streptococcus/genetics/isolation & purification
*Interspersed Repetitive Sequences/genetics
*Gene Transfer, Horizontal
Australia
Genome, Bacterial/genetics
Female
Male
Child
Family Characteristics
Adult
Child, Preschool
Adolescent
Longitudinal Studies
Drug Resistance, Bacterial/genetics
Young Adult

@article {pmid38658407,
year = {2024},
author = {Kuwata, K and Sato-Takabe, Y and Nakai, R and Sugimura, Y and Tazato, N and Kunihiro, T and Morohoshi, S and Iwataki, M and Hamasaki, K and Shiozaki, T},
title = {Novel aerobic anoxygenic phototrophic bacterium Jannaschia pagri sp. nov., isolated from seawater around a fish farm.},
journal = {Antonie van Leeuwenhoek},
volume = {117},
number = {1},
pages = {70},
pmid = {38658407},
issn = {1572-9699},
support = {80635839//MEXT Grants-in-Aid for Young Scientists/ ; JP19H04263//JSPS KAKENHI/ ; },
mesh = {*Phylogeny ; *Seawater/microbiology ; RNA, Ribosomal, 16S/genetics ; Japan ; Aquaculture ; DNA, Bacterial/genetics ; Photosynthesis ; Bacterial Typing Techniques ; Aerobiosis ; Animals ; Bacteriochlorophyll A/analysis ; },
abstract = {The genus Jannaschia is one of the representatives of aerobic anoxygenic phototrophic (AAP) bacteria, which is a strictly aerobic bacterium, producing a photosynthetic pigment bacteriochlorophyll (BChl) a. However, a part of the genus Jannaschia members have not been confirmed the photosynthetic ability. The partly presence of the ability in the genus Jannaschia could suggest the complexity of evolutionary history for anoxygenic photosynthesis in the genus, which is expected as gene loss and/or horizontal gene transfer. Here a novel AAP bacterium designated as strain AI_62[T] (= DSM 115720[ T] = NBRC 115938[ T]), was isolated from coastal seawater around a fish farm in the Uwa Sea, Japan. Its closest relatives were identified as Jannaschia seohaensis SMK-146[ T] (95.6% identity) and J. formosa 12N15[T] (94.6% identity), which have been reported to produce BChl a. The genomic characteristic of strain AI_62[T] clearly showed the possession of the anoxygenic photosynthesis related gene sets. This could be a useful model organism to approach the evolutionary mystery of anoxygenic photosynthesis in the genus Jannaschia. Based on a comprehensive consideration of both phylogenetic and phenotypic characteristics, we propose the classification of a novel species within the genus Jannaschia, designated as Jannaschia pagri sp. nov. The type strain for this newly proposed species is AI_62[T] (= DSM 115720[ T] = NBRC 115938[ T]).},
}

*Phylogeny
*Seawater/microbiology
RNA, Ribosomal, 16S/genetics
Japan
Aquaculture
DNA, Bacterial/genetics
Photosynthesis
Bacterial Typing Techniques
Aerobiosis
Animals
Bacteriochlorophyll A/analysis

@article {pmid38657817,
year = {2024},
author = {Gong, W and Guo, L and Huang, C and Xie, B and Jiang, M and Zhao, Y and Zhang, H and Wu, Y and Liang, H},
title = {A systematic review of antibiotics and antibiotic resistance genes (ARGs) in mariculture wastewater: Antibiotics removal by microalgal-bacterial symbiotic system (MBSS), ARGs characterization on the metagenomic.},
journal = {The Science of the total environment},
volume = {},
number = {},
pages = {172601},
doi = {10.1016/j.scitotenv.2024.172601},
pmid = {38657817},
issn = {1879-1026},
abstract = {Antibiotic residues in mariculture wastewater seriously affect the aquatic environment. Antibiotic Resistance Genes (ARGs) produced under antibiotic stress flow through the environment and eventually enter the human body, seriously affecting human health. Microalgal-bacterial symbiotic system (MBSS) can remove antibiotics from mariculture and reduce the flow of ARGs into the environment. This review encapsulates the present scenario of mariculture wastewater, the removal mechanism of MBSS for antibiotics, and the biomolecular information under metagenomic assay. When confronted with antibiotics, there was a notable augmentation in the extracellular polymeric substances (EPS) content within MBSS, along with a concurrent elevation in the proportion of protein (PN) constituents within the EPS, which limits the entry of antibiotics into the cellular interior. Quorum sensing stimulates the microorganisms to produce biological responses (DNA synthesis - for adhesion) through signaling. Oxidative stress promotes gene expression (coupling, conjugation) to enhance horizontal gene transfer (HGT) in MBSS. The microbial community under metagenomic detection is dominated by aerobic bacteria in the bacterial-microalgal system. Compared to aerobic bacteria, anaerobic bacteria had the significant advantage of decreasing the distribution of ARGs. Overall, MBSS exhibits remarkable efficacy in mitigating the challenges posed by antibiotics and resistant genes from mariculture wastewater.},
}

@article {pmid38651513,
year = {2024},
author = {Gomathinayagam, S and Kodiveri Muthukaliannan, G},
title = {Dynamics of antibiotic resistance genes in plasmids and bacteriophages.},
journal = {Critical reviews in microbiology},
volume = {},
number = {},
pages = {1-10},
doi = {10.1080/1040841X.2024.2339262},
pmid = {38651513},
issn = {1549-7828},
abstract = {This brief review explores the intricate interplay between bacteriophages and plasmids in the context of antibiotic resistance gene (ARG) dissemination. Originating from studies in the late 1950s, the review traces the evolution of knowledge regarding extrachromosomal factors facilitating horizontal gene transfer and adaptation in bacteria. Analyzing the gene repertoires of plasmids and bacteriophages, the study highlights their contributions to bacterial evolution and adaptation. While plasmids encode essential and accessory genes influencing host characteristics, bacteriophages carry auxiliary metabolic genes (AMGs) that augment host metabolism. The debate on phages carrying ARGs is explored through a critical evaluation of various studies, revealing contrasting findings from researchers. Additionally, the review addresses the interplay between prophages and plasmids, underlining their similarities and divergences. Based on the available literature evidence, we conclude that plasmids generally encode ARGs while bacteriophages typically do not contain ARGs. But extra-chromosomaly present prophages with plasmid characteristics can encode and disseminate ARGs.},
}

@article {pmid38648967,
year = {2024},
author = {Se, J and Xie, Y and Ma, Q and Zhu, L and Fu, Y and Xu, X and Shen, C and Nannipieri, P},
title = {Drying-wetting cycle enhances stress resistance of Escherichia coli O157:H7 in a model soil.},
journal = {Environmental pollution (Barking, Essex : 1987)},
volume = {},
number = {},
pages = {123988},
doi = {10.1016/j.envpol.2024.123988},
pmid = {38648967},
issn = {1873-6424},
abstract = {Outbreaks of Escherichia coli (E. coli) O157:H7 in farms are often triggered by heavy rains and flooding. Most cells die with the decreasing of soil moisture, while few cells enter a dormant state and then resuscitate after rewetting. The resistance of dormant cells to stress has been extensively studied, whereas the molecular mechanisms of the cross-resistance development of the resuscitated cells are poorly known. We performed a comparative proteomic analysis on O157:H7 before and after undergoing soil dry-wet alternation. A differential expression of 820 proteins was identified in resuscitated cells compared to exponential-phase cells, as determined by proteomics analysis. The GO and KEGG pathway enrichment analyses revealed that up-regulated proteins were associated with oxidative phosphorylation, glycolysis/gluconeogenesis, the citrate cycle (TCA cycle), aminoacyl-tRNA biosynthesis, ribosome activity, and transmembrane transporters, indicating increased energy production and protein synthesis in resuscitated O157:H7. Moreover, proteins related to acid, osmotic, heat, oxidative, antibiotic stress and horizontal gene transfer efficiency were up-regulated, suggesting a potential improvement in stress resistance. Subsequent validation experiments demonstrated that the survival rates of the resuscitated cells were 476.54 and 7786.34 times higher than the exponential-phase cells, with pH levels of 1.5 and 2.5, respectively. Similarly, resuscitated cells showed higher survival rates under osmotic stress, with 7.5%, 15%, and 30% NaCl resulting in survival rates that were 460.58, 1974.55, and 3475.31 times higher. Resuscitated cells also exhibited increased resistance to heat stress, with survival rates 69.64 and 139.72 times higher at 55°C and 90°C, respectively. Furthermore, the horizontal gene transfer (HGT) efficiency of resuscitated cells was significantly higher (153.12-fold) compared to exponential phase cells. This study provides new insights into bacteria behavior under changing soil moisture and this may explain O157:H7 outbreaks following rainfall and flooding, as the dry-wet cycle promotes stress cross-resistance development.},
}

@article {pmid38647527,
year = {2024},
author = {Ruhluel, D and Fisher, L and Barton, TE and Leighton, H and Kumar, S and Morillo, PA and O'Brien, S and Fothergill, JL and Neill, DR},
title = {Secondary messenger signalling influences Pseudomonas aeruginosa adaptation to sinus and lung environments.},
journal = {The ISME journal},
volume = {},
number = {},
pages = {},
doi = {10.1093/ismejo/wrae065},
pmid = {38647527},
issn = {1751-7370},
abstract = {Pseudomonas aeruginosa is a cause of chronic respiratory tract infections in people with cystic fibrosis (CF), non-CF bronchiectasis and chronic obstructive pulmonary disease. Prolonged infection allows accumulation of mutations and horizontal gene transfer, increasing the likelihood of adaptive phenotypic traits. Adaptation is proposed to arise first in bacterial populations colonising upper airway environments. Here, we model this process using an experimental evolution approach. P. aeruginosa PAO1, which is not airway adapted, was serially passaged, separately, in media chemically reflective of upper or lower airway environments. To explore whether the CF environment selects for unique traits, we separately passaged PAO1 in airway-mimicking media with or without CF-specific factors. Our findings demonstrated that all airway environments - sinus and lungs, under CF and non-CF conditions - selected for loss of twitching motility, increased resistance to multiple antibiotic classes and a hyper-biofilm phenotype. These traits conferred increased airway colonisation potential in an in vivo model. CF-like conditions exerted stronger selective pressures, leading to emergence of more pronounced phenotypes. Loss of twitching was associated with mutations in type IV pili genes. Type IV pili mediate surface attachment, twitching and induction of cAMP signalling. We additionally identified multiple evolutionary routes to increased biofilm formation involving regulation of cyclic-di-GMP signalling. These included loss of function mutations in bifA and dipA phosphodiesterase genes and activating mutations in the siaA phosphatase. These data highlight that airway environments select for traits associated with sessile lifestyles and suggest upper airway niches support emergence of phenotypes that promote establishment of lung infection.},
}

@article {pmid38643972,
year = {2024},
author = {Kogay, R and Wolf, YI and Koonin, EV},
title = {Defence systems and horizontal gene transfer in bacteria.},
journal = {Environmental microbiology},
volume = {26},
number = {4},
pages = {e16630},
pmid = {38643972},
issn = {1462-2920},
support = {Z01 LM000073/ImNIH/Intramural NIH HHS/United States ; },
mesh = {*Gene Transfer, Horizontal ; *Bacteria/genetics/virology ; *CRISPR-Cas Systems ; Genome, Bacterial ; Interspersed Repetitive Sequences ; Bacteriophages/genetics ; Evolution, Molecular ; Prophages/genetics ; },
abstract = {Horizontal gene transfer (HGT) is a fundamental process in prokaryotic evolution, contributing significantly to diversification and adaptation. HGT is typically facilitated by mobile genetic elements (MGEs), such as conjugative plasmids and phages, which often impose fitness costs on their hosts. However, a considerable number of bacterial genes are involved in defence mechanisms that limit the propagation of MGEs, suggesting they may actively restrict HGT. In our study, we investigated whether defence systems limit HGT by examining the relationship between the HGT rate and the presence of 73 defence systems across 12 bacterial species. We discovered that only six defence systems, three of which were different CRISPR-Cas subtypes, were associated with a reduced gene gain rate at the species evolution scale. Hosts of these defence systems tend to have a smaller pangenome size and fewer phage-related genes compared to genomes without these systems. This suggests that these defence mechanisms inhibit HGT by limiting prophage integration. We hypothesize that the restriction of HGT by defence systems is species-specific and depends on various ecological and genetic factors, including the burden of MGEs and the fitness effect of HGT in bacterial populations.},
}

*Gene Transfer, Horizontal
*Bacteria/genetics/virology
*CRISPR-Cas Systems
Genome, Bacterial
Interspersed Repetitive Sequences
Bacteriophages/genetics
Evolution, Molecular
Prophages/genetics

@article {pmid38643216,
year = {2024},
author = {Bartoš, O and Chmel, M and Swierczková, I},
title = {The overlooked evolutionary dynamics of 16S rRNA revises its role as the "gold standard" for bacterial species identification.},
journal = {Scientific reports},
volume = {14},
number = {1},
pages = {9067},
pmid = {38643216},
issn = {2045-2322},
support = {MO1012//Ministry of Defence, Czech Republic/ ; },
mesh = {RNA, Ribosomal, 16S/genetics ; Phylogeny ; *Biological Evolution ; Sequence Analysis, DNA ; },
abstract = {The role of 16S rRNA has been and largely remains crucial for the identification of microbial organisms. Although 16S rRNA could certainly be described as one of the most studied sequences ever, the current view of it remains somewhat ambiguous. While some consider 16S rRNA to be a variable marker with resolution power down to the strain level, others consider them to be living fossils that carry information about the origin of domains of cellular life. We show that 16S rRNA is clearly an evolutionarily very rigid sequence, making it a largely unique and irreplaceable marker, but its applicability beyond the genus level is highly limited. Interestingly, it seems that the evolutionary rigidity is not driven by functional constraints of the sequence (RNA-protein interactions), but rather results from the characteristics of the host organism. Our results suggest that, at least in some lineages, Horizontal Gene Transfer (HGT) within genera plays an important role for the evolutionary non-dynamics (stasis) of 16S rRNA. Such genera exhibit an apparent lack of diversification at the 16S rRNA level in comparison to the rest of a genome. However, why it is limited specifically and solely to 16S rRNA remains enigmatic.},
}

RNA, Ribosomal, 16S/genetics
Phylogeny
*Biological Evolution
Sequence Analysis, DNA

@article {pmid38642082,
year = {2024},
author = {Singh, CK and Sodhi, KK and Shree, P and Nitin, V},
title = {Heavy Metals as Catalysts in the Evolution of Antimicrobial Resistance and the Mechanisms Underpinning Co-selection.},
journal = {Current microbiology},
volume = {81},
number = {6},
pages = {148},
pmid = {38642082},
issn = {1432-0991},
mesh = {Anti-Bacterial Agents/pharmacology ; Drug Resistance, Bacterial ; *Metals, Heavy ; Bacteria/genetics ; *Environmental Pollutants ; },
abstract = {The menace caused by antibiotic resistance in bacteria is acknowledged on a global scale. Concerns over the same are increasing because of the selection pressure exerted by a huge number of different antimicrobial agents, including heavy metals. Heavy metals are non-metabolizable and recalcitrant to degradation, therefore the bacteria can expel the pollutants out of the system and make it less harmful via different mechanisms. The selection of antibiotic-resistant bacteria may be influenced by heavy metals present in environmental reservoirs. Through co-resistance and cross-resistance processes, the presence of heavy metals in the environment can act as co-selecting agents, hence increasing resistance to both heavy metals and antibiotics. The horizontal gene transfer or mutation assists in the selection of mutant bacteria resistant to the polluted environment. Hence, bioremediation and biodegradation are sustainable methods for the natural clean-up of pollutants. This review sheds light on the occurrence of metal and antibiotic resistance in the environment via the co-resistance and cross-resistance mechanisms underpinning co-selection emphasizing the dearth of studies that specifically examine the method of co-selection in clinical settings. Furthermore, it is advised that future research incorporate both culture- and molecular-based methodologies to further our comprehension of the mechanisms underlying bacterial co- and cross-resistance to antibiotics and heavy metals.},
}

Anti-Bacterial Agents/pharmacology
Drug Resistance, Bacterial
*Metals, Heavy
Bacteria/genetics
*Environmental Pollutants

@article {pmid38641304,
year = {2024},
author = {Sha, G and Wu, Z and Chen, T and Zhang, G and Shen, J and Zhao, X and Wang, L},
title = {Mechanisms for more efficient antibiotics and antibiotic resistance genes removal during industrialized treatment of over 200 tons of tylosin and spectinomycin mycelial dregs by integrated meta-omics.},
journal = {Bioresource technology},
volume = {},
number = {},
pages = {130715},
doi = {10.1016/j.biortech.2024.130715},
pmid = {38641304},
issn = {1873-2976},
abstract = {To mitigate the environmental risks posed by the accumulation of antibiotic mycelial dregs (AMDs), this study first attempted over 200 tons of mass production fermentation (MP) using tylosin and spectinomycin mycelial dregs alongside pilot-scale fermentation (PS) for comparison, utilizing the integrated-omics and qPCR approaches. Co-fermentation results showed that both antibiotics were effectively removed in all treatments, with an average removal rate of 92%. Antibiotic resistance gene (ARG)-related metabolic pathways showed that rapid degradation of antibiotics was associated with enzymes that inactivate macrolides and aminoglycosides (e.g., K06979, K07027, K05593). Interestingly, MP fermentations with optimized conditions had more efficient ARGs removal because homogenization permitted faster microbial succession, with more stable removal of antibiotic resistant bacteria and mobile genetic elements. Moreover, Bacillus reached 75% and secreted antioxidant enzymes that might inhibit horizontal gene transfer of ARGs. The findings confirmed the advantages of MP fermentation and provided a scientific basis for other AMDs.},
}

@article {pmid38641198,
year = {2024},
author = {Ouzounis, CA},
title = {The Net of Life, a short story: Intricate patterns of gene flows across hundreds of extant genomes, all the way to LUCA.},
journal = {Bio Systems},
volume = {},
number = {},
pages = {105199},
doi = {10.1016/j.biosystems.2024.105199},
pmid = {38641198},
issn = {1872-8324},
abstract = {Over the past quarter-century, the field of evolutionary biology has been transformed by the emergence of complete genome sequences and the conceptual framework known as the 'Net of Life.' This paradigm shift challenges traditional notions of evolution as a tree-like process, emphasizing the complex, interconnected network of gene flow that may blur the boundaries between distinct lineages. In this context, gene loss, rather than horizontal gene transfer, is the primary driver of gene content, with vertical inheritance playing a principal role. The 'Net of Life' not only impacts our understanding of genome evolution but also has profound implications for classification systems, the rapid appearance of new traits, and the spread of diseases. Here, we explore the core tenets of the 'Net of Life' and its implications for genome-scale phylogenetic divergence, providing a comprehensive framework for further investigations in evolutionary biology.},
}

@article {pmid38641137,
year = {2024},
author = {De, R and Jani, M and Azad, RK},
title = {DICEP: An integrative approach to augmenting genomic island detection.},
journal = {Journal of biotechnology},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.jbiotec.2024.04.011},
pmid = {38641137},
issn = {1873-4863},
abstract = {Mobilization of clusters of genes called genomic islands (GIs) across bacterial lineages facilitates dissemination of traits, such as, resistance against antibiotics, virulence or hypervirulence, and versatile metabolic capabilities. Robust delineation of GIs is critical to understanding bacterial evolution that has a vast impact on different life forms. Methods for identification of GIs exploit different evolutionary features or signals encoded within the genomes of bacteria, however, the current state-of-the-art in GI detection still leaves much to be desired. Here, we have taken a combinatorial approach that accounted for GI specific features such as compositional bias, aberrant phyletic pattern, and marker gene enrichment within an integrative framework to delineate GIs in bacterial genomes. Our GI prediction tool, DICEP, was assessed on simulated genomes and well-characterized bacterial genomes. DICEP compared favorably with current GI detection tools on real and synthetic datasets.},
}

@article {pmid38641096,
year = {2024},
author = {Liu, Y and Chu, K and Hua, Z and Li, Q and Lu, Y and Ye, F and Dong, Y and Li, X},
title = {Dynamics of antibiotic resistance genes in the sediments of a water-diversion lake and its human exposure risk behaviour.},
journal = {The Science of the total environment},
volume = {},
number = {},
pages = {172563},
doi = {10.1016/j.scitotenv.2024.172563},
pmid = {38641096},
issn = {1879-1026},
abstract = {The dynamics and exposure risk behaviours of antibiotic resistance genes (ARGs) in the sediments of water-diversion lakes remain poorly understood. In this study, spatiotemporal investigations of ARG profiles in sediments targeting non-water (NWDP) and water diversion periods (WDP) were conducted in Luoma Lake, a typical water-diversion lake, and an innovative dynamics-based risk assessment framework was constructed to evaluate ARG exposure risks to local residents. ARGs in sediments were significantly more abundant in the WDP than in the NWDP, but there was no significant variation in their spatial distribution in either period. Moreover, the pattern of ARG dissemination in sediments was unchanged between the WDP and NWDP, with horizontal gene transfer (HGT) and vertical gene transfer (VGT) contributing to ARG dissemination in both periods. However, water diversion altered the pattern in lake water, with HGT and VGT in the NWDP but only HGT in the WDP, which were critical pathways for the dissemination of ARGs. The significantly lower ARG sediment-water partition coefficient in the WDP indicated that water diversion could shift the fate of ARGs and facilitate their aqueous partitioning. Risk assessment showed that all age groups faced a higher human exposure risk of ARGs (HERA) in the WDP than in the NWDP, with the 45-59 age group having the highest risk. Furthermore, HERA increased overall with the bacterial carrying capacity in the local environment and peaked when the carrying capacity reached three (NWDP) or four (WDP) orders of magnitude higher than the observed bacterial population. HGT and VGT promoted, whereas ODF covering gene mutation and loss mainly reduced HERA in the lake. As the carrying capacity increased, the relative contribution of ODF to HERA remained relatively stable, whereas the dominant mechanism of HERA development shifted from HGT to VGT.},
}

@article {pmid38640666,
year = {2024},
author = {Xie, S and Hamid, N and Zhang, T and Zhang, Z and Peng, L},
title = {Unraveling the nexus: Microplastics, antibiotics, and ARGs interactions, threats and control in aquaculture - A review.},
journal = {Journal of hazardous materials},
volume = {471},
number = {},
pages = {134324},
doi = {10.1016/j.jhazmat.2024.134324},
pmid = {38640666},
issn = {1873-3336},
abstract = {In recent years, aquaculture has expanded rapidly to address food scarcity and provides high-quality aquatic products. However, this growth has led to the release of significant effluents, containing emerging contaminants like antibiotics, microplastics (MPs), and antibiotic resistance genes (ARGs). This study investigated the occurrence and interactions of these pollutants in aquaculture environment. Combined pollutants, such as MPs and coexisting adsorbents, were widespread and could include antibiotics, heavy metals, resistance genes, and pathogens. Elevated levels of chemical pollutants on MPs could lead to the emergence of resistance genes under selective pressure, facilitated by bacterial communities and horizontal gene transfer (HGT). MPs acted as vectors, transferring pollutants into the food web. Various technologies, including membrane technology, coagulation, and advanced oxidation, have been trialed for pollutants removal, each with its benefits and drawbacks. Future research should focus on ecologically friendly treatment technologies for emerging contaminants in aquaculture wastewater. This review provided insights into understanding and addressing newly developing toxins, aiming to develop integrated systems for effective aquaculture wastewater treatment.},
}

@article {pmid38638913,
year = {2024},
author = {Liu, F and Luo, Y and Xu, T and Lin, H and Qiu, Y and Li, B},
title = {Current examining methods and mathematical models of horizontal transfer of antibiotic resistance genes in the environment.},
journal = {Frontiers in microbiology},
volume = {15},
number = {},
pages = {1371388},
pmid = {38638913},
issn = {1664-302X},
abstract = {The increasing prevalence of antibiotic resistance genes (ARGs) in the environment has garnered significant attention due to their health risk to human beings. Horizontal gene transfer (HGT) is considered as an important way for ARG dissemination. There are four general routes of HGT, including conjugation, transformation, transduction and vesiduction. Selection of appropriate examining methods is crucial for comprehensively understanding characteristics and mechanisms of different HGT ways. Moreover, combined with the results obtained from different experimental methods, mathematical models could be established and serve as a powerful tool for predicting ARG transfer dynamics and frequencies. However, current reviews of HGT for ARG spread mainly focus on its influencing factors and mechanisms, overlooking the important roles of examining methods and models. This review, therefore, delineated four pathways of HGT, summarized the strengths and limitations of current examining methods, and provided a comprehensive summing-up of mathematical models pertaining to three main HGT ways of conjugation, transformation and transduction. Finally, deficiencies in current studies were discussed, and proposed the future perspectives to better understand and assess the risks of ARG dissemination through HGT.},
}

@article {pmid38638826,
year = {2024},
author = {Nasrollahian, S and Graham, JP and Halaji, M},
title = {A review of the mechanisms that confer antibiotic resistance in pathotypes of E. coli.},
journal = {Frontiers in cellular and infection microbiology},
volume = {14},
number = {},
pages = {1387497},
pmid = {38638826},
issn = {2235-2988},
abstract = {The dissemination of antibiotic resistance in Escherichia coli poses a significant threat to public health worldwide. This review provides a comprehensive update on the diverse mechanisms employed by E. coli in developing resistance to antibiotics. We primarily focus on pathotypes of E. coli (e.g., uropathogenic E. coli) and investigate the genetic determinants and molecular pathways that confer resistance, shedding light on both well-characterized and recently discovered mechanisms. The most prevalent mechanism continues to be the acquisition of resistance genes through horizontal gene transfer, facilitated by mobile genetic elements such as plasmids and transposons. We discuss the role of extended-spectrum β-lactamases (ESBLs) and carbapenemases in conferring resistance to β-lactam antibiotics, which remain vital in clinical practice. The review covers the key resistant mechanisms, including: 1) Efflux pumps and porin mutations that mediate resistance to a broad spectrum of antibiotics, including fluoroquinolones and aminoglycosides; 2) adaptive strategies employed by E. coli, including biofilm formation, persister cell formation, and the activation of stress response systems, to withstand antibiotic pressure; and 3) the role of regulatory systems in coordinating resistance mechanisms, providing insights into potential targets for therapeutic interventions. Understanding the intricate network of antibiotic resistance mechanisms in E. coli is crucial for the development of effective strategies to combat this growing public health crisis. By clarifying these mechanisms, we aim to pave the way for the design of innovative therapeutic approaches and the implementation of prudent antibiotic stewardship practices to preserve the efficacy of current antibiotics and ensure a sustainable future for healthcare.},
}

@article {pmid38626743,
year = {2024},
author = {Sewell, HL and Criddle, CS and Woo, SG and Kim, S and Müller, JA and Kaster, AK},
title = {Pseudomonas stutzeri KC carries the pdt genes for carbon tetrachloride degradation on an integrative and conjugative element.},
journal = {Microbial physiology},
volume = {},
number = {},
pages = {},
doi = {10.1159/000538783},
pmid = {38626743},
issn = {2673-1673},
abstract = {Pseudomonas stutzeri KC can rapidly degrade carbon tetrachloride (CCl4) to CO2 by a fortuitous reaction with pyridine-2,6-bis(thiocarboxylic acid), a metal chelator encoded by pdt genes. These genes were first identified after a spontaneous mutant, strain CTN1, lost the ability to degrade CCl4. Here we report the complete genome of strain KC and show that these pdt genes are located on an integrative and conjugative element (ICE), designated ICEPsstKC. Comparative genome analyses revealed homologues of pdt genes in genomes of members of other gammaproteobacterial orders. Discrepancies between the tree topologies of the deduced pdt gene products and the host phylogeny based on 16S rRNA provided evidence for horizontal gene transfer (HGT) in several sequenced strains of these orders. In addition to ICEPsstKC, HGT may be have been facilitated by other mobile genetic elements, as indicated by the location of the pdt gene cluster adjacent to fragments of other ICEs and prophages in several genome assemblies. We could here show that the majority of cells from the culture collection DSMZ had lost the ICE. The presence of the pdt gene cluster on mobile genetic elements has important implications for the bioremediation of CCl4 for bioremediation of CCl4 and needs consideration when selecting suitable strains.},
}

@article {pmid38618705,
year = {2024},
author = {Sarkar, S and Anyaso-Samuel, S and Qiu, P and Datta, S},
title = {Multiblock partial least squares and rank aggregation: Applications to detection of bacteriophages associated with antimicrobial resistance in the presence of potential confounding factors.},
journal = {Statistics in medicine},
volume = {},
number = {},
pages = {},
doi = {10.1002/sim.10058},
pmid = {38618705},
issn = {1097-0258},
abstract = {Urban environments, characterized by bustling mass transit systems and high population density, host a complex web of microorganisms that impact microbial interactions. These urban microbiomes, influenced by diverse demographics and constant human movement, are vital for understanding microbial dynamics. We explore urban metagenomics, utilizing an extensive dataset from the Metagenomics & Metadesign of Subways & Urban Biomes (MetaSUB) consortium, and investigate antimicrobial resistance (AMR) patterns. In this pioneering research, we delve into the role of bacteriophages, or "phages"-viruses that prey on bacteria and can facilitate the exchange of antibiotic resistance genes (ARGs) through mechanisms like horizontal gene transfer (HGT). Despite their potential significance, existing literature lacks a consensus on their significance in ARG dissemination. We argue that they are an important consideration. We uncover that environmental variables, such as those on climate, demographics, and landscape, can obscure phage-resistome relationships. We adjust for these potential confounders and clarify these relationships across specific and overall antibiotic classes with precision, identifying several key phages. Leveraging machine learning tools and validating findings through clinical literature, we uncover novel associations, adding valuable insights to our comprehension of AMR development.},
}

@article {pmid38617843,
year = {2024},
author = {Guinet, B and Leobold, M and Herniou, EA and Bloin, P and Burlet, N and Bredlau, J and Navratil, V and Ravallec, M and Uzbekov, R and Kester, K and Gundersen Rindal, D and Drezen, JM and Varaldi, J and Bézier, A},
title = {A novel and diverse family of filamentous DNA viruses associated with parasitic wasps.},
journal = {Virus evolution},
volume = {10},
number = {1},
pages = {veae022},
pmid = {38617843},
issn = {2057-1577},
abstract = {Large dsDNA viruses from the Naldaviricetes class are currently composed of four viral families infecting insects and/or crustaceans. Since the 1970s, particles described as filamentous viruses (FVs) have been observed by electronic microscopy in several species of Hymenoptera parasitoids but until recently, no genomic data was available. This study provides the first comparative morphological and genomic analysis of these FVs. We analyzed the genomes of seven FVs, six of which were newly obtained, to gain a better understanding of their evolutionary history. We show that these FVs share all genomic features of the Naldaviricetes while encoding five specific core genes that distinguish them from their closest relatives, the Hytrosaviruses. By mining public databases, we show that FVs preferentially infect Hymenoptera with parasitoid lifestyle and that these viruses have been repeatedly integrated into the genome of many insects, particularly Hymenoptera parasitoids, overall suggesting a long-standing specialization of these viruses to parasitic wasps. Finally, we propose a taxonomical revision of the class Naldaviricetes in which FVs related to the Leptopilina boulardi FV constitute a fifth family. We propose to name this new family, Filamentoviridae.},
}

@article {pmid38617331,
year = {2024},
author = {Lyulina, AS and Liu, Z and Good, BH},
title = {Linkage equilibrium between rare mutations.},
journal = {bioRxiv : the preprint server for biology},
volume = {},
number = {},
pages = {},
doi = {10.1101/2024.03.28.587282},
pmid = {38617331},
abstract = {Recombination breaks down genetic linkage by reshuffling existing variants onto new genetic backgrounds. These dynamics are traditionally quantified by examining the correlations between alleles, and how they decay as a function of the recombination rate. However, the magnitudes of these correlations are strongly influenced by other evolutionary forces like natural selection and genetic drift, making it difficult to tease out the effects of recombination. Here we introduce a theoretical framework for analyzing an alternative family of statistics that measure the homoplasy produced by recombination. We derive analytical expressions that predict how these statistics depend on the rates of recombination and recurrent mutation, the strength of negative selection and genetic drift, and the present-day frequencies of the mutant alleles. We find that the degree of homoplasy can strongly depend on this frequency scale, which reflects the underlying timescales over which these mutations occurred. We show how these scaling properties can be used to isolate the effects of recombination, and discuss their implications for the rates of horizontal gene transfer in bacteria.},
}

@article {pmid38615644,
year = {2024},
author = {Fu, X and Gao, J and Wang, Q and Chen, H and Liu, Y and Zeng, L and Yuan, Y and Xu, H},
title = {Mechanisms on the removal of gram-negative/positive antibiotic resistant bacteria and inhibition of horizontal gene transfer by ferrate coupled with peroxydisulfate or peroxymonosulfate.},
journal = {Journal of hazardous materials},
volume = {470},
number = {},
pages = {134254},
doi = {10.1016/j.jhazmat.2024.134254},
pmid = {38615644},
issn = {1873-3336},
abstract = {The existence of antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) has been a global public environment and health issue. Due to the different cell structures, gram-positive/negative ARB exhibit various inactivation mechanisms in water disinfection. In this study, a gram-negative ARB Escherichia coli DH5α (E. coli DH5α) was used as a horizontal gene transfer (HGT) donor, while a gram-positive ARB Bacillus as a recipient. To develop an efficient and engineering applicable method in water disinfection, ARB and ARGs removal efficiency of Fe(VI) coupled peroxydisulfate (PDS) or peroxymonosulfate (PMS) was compared, wherein hydroxylamine (HA) was added as a reducing agent. The results indicated that Fe(VI)/PMS/HA showed higher disinfection efficiency than Fe(VI)/PDS/HA. When the concentration of each Fe(VI), PMS, HA was 0.48 mM, 5.15 log E. coli DH5α and 3.57 log Bacillus lost cultivability, while the proportion of recovered cells was 0.0017 % and 0.0566 %, respectively, and HGT was blocked. Intracellular tetA was reduced by 2.49 log. Fe(IV) and/or Fe(V) were proved to be the decisive reactive species. Due to the superiority of low cost as well as high efficiency and practicality, Fe(VI)/PMS/HA has significant application potential in ARB, ARGs removal and HGT inhibition, offering a new insight for wastewater treatment.},
}

@article {pmid38609370,
year = {2024},
author = {Quinones-Olvera, N and Owen, SV and McCully, LM and Marin, MG and Rand, EA and Fan, AC and Martins Dosumu, OJ and Paul, K and Sanchez Castaño, CE and Petherbridge, R and Paull, JS and Baym, M},
title = {Diverse and abundant phages exploit conjugative plasmids.},
journal = {Nature communications},
volume = {15},
number = {1},
pages = {3197},
pmid = {38609370},
issn = {2041-1723},
support = {R35GM133700//U.S. Department of Health & Human Services | NIH | National Institute of General Medical Sciences (NIGMS)/ ; T32GM135014//U.S. Department of Health & Human Services | NIH | National Institute of General Medical Sciences (NIGMS)/ ; IOS-2331228//NSF | BIO | Division of Integrative Organismal Systems (IOS)/ ; 1764269//NSF | Directorate for Mathematical & Physical Sciences | Division of Mathematical Sciences (DMS)/ ; },
mesh = {*Bacteriophages/genetics ; Wastewater ; Biological Evolution ; Biotechnology ; Cell Membrane ; },
abstract = {Phages exert profound evolutionary pressure on bacteria by interacting with receptors on the cell surface to initiate infection. While the majority of phages use chromosomally encoded cell surface structures as receptors, plasmid-dependent phages exploit plasmid-encoded conjugation proteins, making their host range dependent on horizontal transfer of the plasmid. Despite their unique biology and biotechnological significance, only a small number of plasmid-dependent phages have been characterized. Here we systematically search for new plasmid-dependent phages targeting IncP and IncF plasmids using a targeted discovery platform, and find that they are common and abundant in wastewater, and largely unexplored in terms of their genetic diversity. Plasmid-dependent phages are enriched in non-canonical types of phages, and all but one of the 65 phages we isolated were non-tailed, and members of the lipid-containing tectiviruses, ssDNA filamentous phages or ssRNA phages. We show that plasmid-dependent tectiviruses exhibit profound differences in their host range which is associated with variation in the phage holin protein. Despite their relatively high abundance in wastewater, plasmid-dependent tectiviruses are missed by metaviromic analyses, underscoring the continued importance of culture-based phage discovery. Finally, we identify a tailed phage dependent on the IncF plasmid, and find related structural genes in phages that use the orthogonal type 4 pilus as a receptor, highlighting the evolutionarily promiscuous use of these distinct contractile structures by multiple groups of phages. Taken together, these results indicate plasmid-dependent phages play an under-appreciated evolutionary role in constraining horizontal gene transfer via conjugative plasmids.},
}

*Bacteriophages/genetics
Wastewater
Biological Evolution
Biotechnology
Cell Membrane

@article {pmid38608575,
year = {2024},
author = {Xu, Z and Hu, S and Zhao, D and Xiong, J and Li, C and Ma, Y and Li, S and Huang, B and Pan, X},
title = {Molybdenum disulfide nanosheets promote the plasmid-mediated conjugative transfer of antibiotic resistance genes.},
journal = {Journal of environmental management},
volume = {358},
number = {},
pages = {120827},
doi = {10.1016/j.jenvman.2024.120827},
pmid = {38608575},
issn = {1095-8630},
abstract = {The environmental safety of nanoscale molybdenum disulfide (MoS2) has attracted considerable attention, but its influence on the horizontal migration of antibiotic resistance genes and the ecological risks entailed have not been reported. This study addressed the influence of exposure to MoS2 at different concentrations up to 100 mg/L on the conjugative transfer of antibiotic resistance genes carried by RP4 plasmids with two strains of Escherichia coli. As a result, MoS2 facilitated RP4 plasmid-mediated conjugative transfer in a dose-dependent manner. The conjugation of RP4 plasmids was enhanced as much as 7-fold. The promoting effect is mainly attributable to increased membrane permeability, oxidative stress induced by reactive oxygen species, changes in extracellular polymer secretion and differential expression of the genes involved in horizontal gene transfer. The data highlight the distinct dose dependence of the conjugative transfer of antibiotic resistance genes and the need to improve awareness of the ecological and health risks of nanoscale transition metal dichalcogenides.},
}

@article {pmid38608246,
year = {2024},
author = {Yi, S and Zhou, K and Xu, X},
title = {Characterization of erm(B)-Carrying Integrative and Conjugative Elements Transferred from Streptococcus anginosus to Other Streptococci and Enterococci.},
journal = {Microbial drug resistance (Larchmont, N.Y.)},
volume = {},
number = {},
pages = {},
doi = {10.1089/mdr.2023.0342},
pmid = {38608246},
issn = {1931-8448},
abstract = {Integrative and conjugative elements (ICEs) are important vectors of lateral gene transfer and contribute to the evolution of bacterial pathogens. However, studies on the transfer among species and the physiological consequences of ICEs are rare. The objective of this study was to investigate the cross-species transferability of newly identified erm(B)-carried ICE in Streptococcus anginosus San95 and its physiological consequences after transfer. The erm(B)-carried ICE, characterized by a triple serine integrase module, integrated into hsdM genes, thus designated ICESan95_hsdM. Analysis of ICESan95_hsdM revealed 32 additional ICESan95-like ICEs in the available NCBI genome (n = 24) and sequence of clinical isolates (n = 8). Polymerase chain reaction (PCR) was used to evaluate the 467 clinical isolates, of which 84 were positive for core genes (integrase, relaxase, and T4SS genes) of ICESan95_hsdM. Cross-species transfer experiments demonstrated that ICESan95_hsdM could transfer from S. anginosus to different streptococcal and enterococcal recipients. Growth and competitive culture assays showed acquisition of ICESan95_hsdM incurred no fitness cost. Our work discovered a group of ICEs in Streptococci and Enterococci. For the first time, we demonstrated the broad cross-species transferability to different species or genera of ICEs with no fitness cost that enables commensal S. anginosus to deliver antimicrobial resistance genes to other streptococci and enterococci.},
}

@article {pmid38605260,
year = {2024},
author = {Rafiq, MS and Shabbir, MA and Raza, A and Irshad, S and Asghar, A and Maan, MK and Gondal, MA and Hao, H},
title = {CRISPR-Cas System: A New Dawn to Combat Antibiotic Resistance.},
journal = {BioDrugs : clinical immunotherapeutics, biopharmaceuticals and gene therapy},
volume = {},
number = {},
pages = {},
pmid = {38605260},
issn = {1179-190X},
support = {32172914//the National Natural Science Foundation of China/ ; 2021YFD1800600//Key Technology Research and Development Program of Shandong Province/ ; . 2662022DKYJC005//the Fundamental Research Funds for the Central Universities/ ; },
abstract = {Antimicrobial resistance (AMR) can potentially harm global public health. Horizontal gene transfer (HGT), which speeds up the emergence of AMR and increases the burden of drug resistance in mobile genetic elements (MGEs), is the primary method by which AMR genes are transferred across bacterial pathogens. New approaches are urgently needed to halt the spread of bacterial diseases and antibiotic resistance. Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR), an RNA-guided adaptive immune system, protects prokaryotes from foreign DNA like plasmids and phages. This approach may be essential in limiting horizontal gene transfer and halting the spread of antibiotic resistance. The CRISPR-Cas system has been crucial in identifying and understanding resistance mechanisms and developing novel therapeutic approaches. This review article investigates the CRISPR-Cas system's potential as a tool to combat bacterial AMR. Antibiotic-resistant bacteria can be targeted and eliminated by the CRISPR-Cas system. It has been proven to be an efficient method for removing carbapenem-resistant plasmids and regaining antibiotic susceptibility. The CRISPR-Cas system has enormous potential as a weapon against bacterial AMR. It precisely targets and eliminates antibiotic-resistant bacteria, facilitates resistance mechanism identification, and offers new possibilities in diagnostics and therapeutics.},
}

@article {pmid38605009,
year = {2024},
author = {Zorea, A and Pellow, D and Levin, L and Pilosof, S and Friedman, J and Shamir, R and Mizrahi, I},
title = {Plasmids in the human gut reveal neutral dispersal and recombination that is overpowered by inflammatory diseases.},
journal = {Nature communications},
volume = {15},
number = {1},
pages = {3147},
pmid = {38605009},
issn = {2041-1723},
support = {866530//EC | EU Framework Programme for Research and Innovation H2020 | H2020 Priority Excellent Science | H2020 European Research Council (H2020 Excellent Science - European Research Council)/ ; ISF 1947/19//Israel Science Foundation (ISF)/ ; },
abstract = {Plasmids are pivotal in driving bacterial evolution through horizontal gene transfer. Here, we investigated 3467 human gut microbiome samples across continents and disease states, analyzing 11,086 plasmids. Our analyses reveal that plasmid dispersal is predominantly stochastic, indicating neutral processes as the primary driver of their wide distribution. We find that only 20-25% of plasmid DNA is being selected in various disease states, constraining its distribution across hosts. Selective pressures shape specific plasmid segments with distinct ecological functions, influenced by plasmid mobilization lifestyle, antibiotic usage, and inflammatory gut diseases. Notably, these elements are more commonly shared within groups of individuals with similar health conditions, such as Inflammatory Bowel Disease (IBD), regardless of geographic location across continents. These segments contain essential genes such as iron transport mechanisms- a distinctive gut signature of IBD that impacts the severity of inflammation. Our findings shed light on mechanisms driving plasmid dispersal and selection in the human gut, highlighting their role as carriers of vital gene pools impacting bacterial hosts and ecosystem dynamics.},
}

@article {pmid38604355,
year = {2024},
author = {Yin, Z and Liang, J and Zhang, M and Chen, B and Yu, Z and Tian, X and Deng, X and Peng, L},
title = {Pan-genome insights into adaptive evolution of bacterial symbionts in mixed host-microbe symbioses represented by human gut microbiota Bacteroides cellulosilyticus.},
journal = {The Science of the total environment},
volume = {},
number = {},
pages = {172251},
doi = {10.1016/j.scitotenv.2024.172251},
pmid = {38604355},
issn = {1879-1026},
abstract = {Animal hosts harbor diverse assemblages of microbial symbionts that play crucial roles in the host's lifestyle. The link between microbial symbiosis and host development remains poorly understood. In particular, little is known about the adaptive evolution of gut bacteria in host-microbe symbioses. Recently, symbiotic relationships have been categorized as open, closed, or mixed, reflecting their modes of inter-host transmission and resulting in distinct genomic features. Members of the genus Bacteroides are the most abundant human gut microbiota and possess both probiotic and pathogenic potential, providing an excellent model for studying pan-genome evolution in symbiotic systems. Here, we determined the complete genome of an novel clinical strain PL2022, which was isolated from a blood sample and performed pan-genome analyses on a representative set of Bacteroides cellulosilyticus strains to quantify the influence of the symbiotic relationship on the evolutionary dynamics. B. cellulosilyticus exhibited correlated genomic features with both open and closed symbioses, suggesting a mixed symbiosis. An open pan-genome is characterized by abundant accessory gene families, potential horizontal gene transfer (HGT), and diverse mobile genetic elements (MGEs), indicating an innovative gene pool, mainly associated with genomic islands and plasmids. However, massive parallel gene loss, weak purifying selection, and accumulation of positively selected mutations were the main drivers of genome reduction in B. cellulosilyticus. Metagenomic read recruitment analyses showed that B. cellulosilyticus members are globally distributed and active in human gut habitats, in line with predominant vertical transmission in the human gut. However, existence and/or high abundance were also detected in non-intestinal tissues, other animal hosts, and non-host environments, indicating occasional horizontal transmission to new niches, thereby creating arenas for the acquisition of novel genes. This case study of adaptive evolution under a mixed host-microbe symbiosis advances our understanding of symbiotic pan-genome evolution. Our results highlight the complexity of genetic evolution in this unusual intestinal symbiont.},
}

@article {pmid38601936,
year = {2024},
author = {Ortañez, J and Degnan, PH},
title = {Tracking and characterization of a novel conjugative transposon identified by shotgun transposon mutagenesis.},
journal = {Frontiers in microbiology},
volume = {15},
number = {},
pages = {1241582},
pmid = {38601936},
issn = {1664-302X},
abstract = {The horizontal transfer of mobile genetic elements (MGEs) is an essential process determining the functional and genomic diversity of bacterial populations. MGEs facilitate the exchange of fitness determinant genes like antibiotic resistance and virulence factors. Various computational methods exist to identify potential MGEs, but confirming their ability to transfer requires additional experimental approaches. Here, we apply a transposon (Tn) mutagenesis technique for confirming mobilization without the need for targeted mutations. Using this method, we identified two MGEs, including a previously known conjugative transposon (CTn) called BoCTn found in Bacteroides ovatus and a novel CTn, PvCTn, identified in Phocaeicola vulgatus. In addition, Tn mutagenesis and subsequent genetic deletion enabled our characterization of a helix-turn-helix motif gene, BVU3433 which negatively regulates the conjugation efficiency of PvCTn in vitro. Furthermore, our transcriptomics data revealed that BVU3433 plays a crucial role in the repression of PvCTn genes, including genes involved in forming complete conjugation machinery [Type IV Secretion System (T4SS)]. Finally, analysis of individual strain genomes and community metagenomes identified the widespread prevalence of PvCTn-like elements with putative BVU3433 homologs among human gut-associated bacteria. In summary, this Tn mutagenesis mobilization method (TMMM) enables observation of transfer events in vitro and can ultimately be applied in vivo to identify a broader diversity of functional MGEs that may underly the transfer of important fitness determinants.},
}

@article {pmid38601791,
year = {2024},
author = {Babiker, A and Lohsen, S and Van Riel, J and Hjort, K and Weiss, DS and Andersson, DI and Satola, S},
title = {Heteroresistance to piperacillin/tazobactam in Klebsiella pneumoniae is mediated by increased copy number of multiple β-lactamase genes.},
journal = {JAC-antimicrobial resistance},
volume = {6},
number = {2},
pages = {dlae057},
pmid = {38601791},
issn = {2632-1823},
abstract = {BACKGROUND: Piperacillin/tazobactam is a β-lactam/β-lactamase inhibitor combination with a broad spectrum of activity that is often used as empirical and/or targeted therapy among hospitalized patients. Heteroresistance (HR) is a form of antibiotic resistance in which a minority population of resistant cells coexists with a majority susceptible population that has been found to be a cause of antibiotic treatment failure in murine models.

OBJECTIVES: To determine the prevalence of HR and mechanisms of HR to piperacillin/tazobactam among Klebsiella pneumoniae bloodstream infection (BSI) isolates.

MATERIALS: From July 2018 to June 2021, K. pneumoniae piperacillin/tazobactam-susceptible BSI isolates were collected from two tertiary hospitals in Atlanta, GA, USA. Only first isolates from each patient per calendar year were included. Population analysis profiling (PAP) and WGS were performed to identify HR and its mechanisms.

RESULTS: Among 423 K. pneumoniae BSI isolates collected during the study period, 6% (25/423) were found to be HR with a subpopulation surviving above the breakpoint. WGS of HR isolates grown in the presence of piperacillin/tazobactam at concentrations 8-fold that of the MIC revealed copy number changes of plasmid-located β-lactamase genes blaCTX-M-15, blaSHV33, blaOXA-1 and blaTEM-1 by tandem gene amplification or plasmid copy number increase.

CONCLUSIONS: Prevalence of HR to piperacillin/tazobactam among bloodstream isolates was substantial. The HR phenotype appears to be caused by tandem amplification of β-lactamase genes found on plasmids or plasmid copy number increase. This raises the possibility of dissemination of HR through horizontal gene transfer and requires further study.},
}

@article {pmid38601688,
year = {2024},
author = {Ma, X and Yin, Z and Li, H and Guo, J},
title = {Roles of herbivorous insects salivary proteins.},
journal = {Heliyon},
volume = {10},
number = {7},
pages = {e29201},
pmid = {38601688},
issn = {2405-8440},
abstract = {The intricate relationship between herbivorous insects and plants has evolved over millions of years, central to this dynamic interaction are salivary proteins (SPs), which mediate key processes ranging from nutrient acquisition to plant defense manipulation. SPs, sourced from salivary glands, intestinal regurgitation or acquired through horizontal gene transfer, exhibit remarkable functional versatility, influencing insect development, behavior, and adhesion mechanisms. Moreover, SPs play pivotal roles in modulating plant defenses, to induce or inhibit plant defenses as elicitors or effectors. In this review, we delve into the multifaceted roles of SPs in herbivorous insects, highlighting their diverse impacts on insect physiology and plant responses. Through a comprehensive exploration of SP functions, this review aims to deepen our understanding of plant-insect interactions and foster advancements in both fundamental research and practical applications in plant-insect interactions.},
}

@article {pmid38599270,
year = {2024},
author = {Thibodeau, AJ and Barret, M and Mouchetd, F and Nguyen, VX and Pinelli, E},
title = {"The potential contribution of aquatic wildlife to antibiotic resistance dissemination in freshwater ecosystems: A review".},
journal = {Environmental pollution (Barking, Essex : 1987)},
volume = {},
number = {},
pages = {123894},
doi = {10.1016/j.envpol.2024.123894},
pmid = {38599270},
issn = {1873-6424},
abstract = {Antibiotic resistance (AR) is one of the major health threats of our time. The presence of antibiotics in the environment and their continuous release from sewage treatment plants, chemical manufacturing plants and animal husbandry, agriculture and aquaculture, result in constant selection pressure on microbial organisms. This presence leads to the emergence, mobilization, horizontal gene transfer and a selection of antibiotic resistance genes, resistant bacteria and mobile genetic elements. Under these circumstances, aquatic wildlife is impacted in all compartments, including freshwater organisms with partially impermeable microbiota. In this narrative review, recent advancements in terms of occurrence of antibiotics and antibiotic resistance genes in sewage treatment plant effluents source compared to freshwater have been examined, occurrence of antibiotic resistance in wildlife, as well as experiments on antibiotic exposure. Based on this current state of knowledge, we propose the hypothesis that freshwater aquatic wildlife may play a crucial role in the dissemination of antibiotic resistance within the environment. Specifically, we suggest that organisms with high bacterial density tissues, which are partially isolated from the external environment, such as fishes and amphibians, could potentially be reservoirs and amplifiers of antibiotic resistance in the environment, potentially favoring the increase of the abundance of antibiotic resistance genes and resistant bacteria. Potential avenues for further research (trophic transfer, innovative exposure experiment) and action (biodiversity eco-engineering) are finally proposed.},
}

@article {pmid38598950,
year = {2024},
author = {Lei, L and Chen, N and Chen, Z and Zhao, Y and Lin, H and Li, X and Hu, W and Zhang, H and Shi, J and Luo, Y},
title = {Dissemination of antibiotic resistance genes from aboveground sources to groundwater in livestock farms.},
journal = {Water research},
volume = {256},
number = {},
pages = {121584},
doi = {10.1016/j.watres.2024.121584},
pmid = {38598950},
issn = {1879-2448},
abstract = {Antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) are prevalent in various environments on livestock farms, including livestock waste, soil, and groundwater. Contamination of groundwater by ARB and ARGs in livestock farms is a growing concern as it may have potentially huge risks to human health. However, the source of groundwater-borne ARB and ARGs in animal farms remains largely unknown. In this study, different types of samples including groundwater and its potential contamination sources from aboveground (pig feces, wastewater, and soil) from both working and abandoned swine feedlots in southern China were collected and subjected to metagenomic sequencing and ARB isolation. The source tracking based on metagenomic analysis revealed that 56-95 % of ARGs in groundwater was attributable to aboveground sources. Using metagenomic assembly, we found that 45 ARGs predominantly conferring resistance to aminoglycosides, sulfonamides, and tetracyclines could be transferred from the aboveground sources to groundwater, mostly through plasmid-mediated horizontal gene transfer. Furthermore, the full-length nucleotide sequences of sul1, tetA, and TEM-1 detected in ARB isolates exhibited the close evolutionary relationships between aboveground sources and groundwater. Some isolated strains of antibiotic-resistant Pseudomonas spp. from aboveground sources and groundwater had the high similarity (average nucleotide identity > 99 %). Notably, the groundwater-borne ARGs were identified as mainly carried by bacterial pathogens, potentially posing risks to human and animal health. Overall, this study underscores the dissemination of ARGs from aboveground sources to groundwater in animal farms and associated risks.},
}

@article {pmid38598457,
year = {2024},
author = {Gao, X and Xu, L and Zhong, T and Song, X and Zhang, H and Liu, X and Jiang, Y},
title = {The proliferation of antibiotic resistance genes (ARGs) and microbial communities in industrial wastewater treatment plant treating N,N-dimethylformamide (DMF) by AAO process.},
journal = {PloS one},
volume = {19},
number = {4},
pages = {e0299740},
pmid = {38598457},
issn = {1932-6203},
abstract = {The excessive use of antibiotics has resulted in the contamination of the environment with antibiotic resistance genes (ARGs), posing a significant threat to public health. Wastewater treatment plants (WWTPs) are known to be reservoirs of ARGs and considered to be hotspots for horizontal gene transfer (HGT) between bacterial communities. However, most studies focused on the distribution and dissemination of ARGs in hospital and urban WWTPs, and little is known about their fate in industrial WWTPs. In this study, collected the 15 wastewater samples containing N,N-dimethylformamide (DMF) from five stages of the anaerobic anoxic aerobic (AAO) process in an industrial WWTPs. The findings revealed a stepwise decrease in DMF and chemical oxygen demand (COD) content with the progression of treatment. However, the number and abundances of ARGs increase in the effluents of biological treatments. Furthermore, the residues of DMF and the treatment process altered the structure of the bacterial community. The correlation analysis indicated that the shift in bacterial community structures might be the main driver for the dynamics change of ARGs. Interestingly, observed that the AAO process may acted as a microbial source and increased the total abundance of ARGs instead of attenuating it. Additionally, found that non-pathogenic bacteria had higher ARGs abundance than pathogenic bacteria in effluents. The study provides insights into the microbial community structure and the mechanisms that drive the variation in ARGs abundance in industrial WWTPs.},
}

@article {pmid38598029,
year = {2024},
author = {Ramnarine, SDBJ and Jayaraman, J and Ramsubhag, A},
title = {Crucifer Lesion-Associated Xanthomonas Strains Show Multi-Resistance to Heavy Metals and Antibiotics.},
journal = {Current microbiology},
volume = {81},
number = {5},
pages = {136},
pmid = {38598029},
issn = {1432-0991},
support = {CRP.5.APR17.45//University of the West Indies, St. Augustine Campus/ ; },
abstract = {Copper resistance in phytopathogens is a major challenge to crop production globally and is known to be driven by excessive use of copper-based pesticides. However, recent studies have shown co-selection of multiple heavy metal and antibiotic resistance genes in bacteria exposed to heavy metal and xenobiotics, which may impact the epidemiology of plant, animal, and human diseases. In this study, multi-resistance to heavy metals and antibiotics were evaluated in local Xanthomonas campestris pv. campestris (Xcc) and co-isolated Xanthomonas melonis (Xmel) strains from infected crucifer plants in Trinidad. Resistance to cobalt, cadmium, zinc, copper, and arsenic (V) was observed in both Xanthomonas species up to 25 mM. Heavy metal resistance (HMR) genes were found on a small plasmid-derived locus with ~ 90% similarity to a Stenotrophomonas spp. chromosomal locus and a X. perforans pLH3.1 plasmid. The co-occurrence of mobile elements in these regions implies their organization on a composite transposon-like structure. HMR genes in Xcc strains showed the lowest similarity to references, and the cus and ars operons appear to be unique among Xanthomonads. Overall, the similarity of HMR genes to Stenotrophomonas sp. chromosomal genomes suggest their origin in this genus or a related organism and subsequent spread through lateral gene transfer events. Further resistome characterization revealed the presence of small multidrug resistance (SMR), multidrug resistance (MDR) efflux pumps, and bla (Xcc) genes for broad biocide resistance in both species. Concurrently, resistance to antibiotics (streptomycin, kanamycin, tetracycline, chloramphenicol, and ampicillin) up to 1000 µg/mL was confirmed.},
}

@article {pmid38597658,
year = {2024},
author = {Schmid, N and Brandt, D and Walasek, C and Rolland, C and Wittmann, J and Fischer, D and Müsken, M and Kalinowski, J and Thormann, K},
title = {An autonomous plasmid as an inovirus phage satellite.},
journal = {Applied and environmental microbiology},
volume = {},
number = {},
pages = {e0024624},
doi = {10.1128/aem.00246-24},
pmid = {38597658},
issn = {1098-5336},
abstract = {Bacterial viruses (phages) are potent agents of lateral gene transfer and thus are important drivers of evolution. A group of mobile genetic elements, referred to as phage satellites, exploits phages to disseminate their own genetic material. Here, we isolated a novel member of the family Inoviridae, Shewanella phage Dolos, along with an autonomously replicating plasmid, pDolos. Dolos causes a chronic infection in its host Shewanella oneidensis by phage production with only minor effects on the host cell proliferation. When present, plasmid pDolos hijacks Dolos functions to be predominantly packaged into phage virions and released into the environment and, thus, acts as a phage satellite. pDolos can disseminate further genetic material encoding, e.g., resistances or fluorophores to host cells sensitive to Dolos infection. Given the rather simple requirements of a plasmid for takeover of an inovirus and the wide distribution of phages of this group, we speculate that similar phage-satellite systems are common among bacteria.IMPORTANCEPhage satellites are mobile genetic elements, which hijack phages to be transferred to other host cells. The vast majority of these phage satellites integrate within the host's chromosome, and they all carry remaining phage genes. Here, we identified a novel phage satellite, pDolos, which uses an inovirus for dissemination. pDolos (i) remains as an autonomously replicating plasmid within its host, (ii) does not carry recognizable phage genes, and (iii) is smaller than any other phage satellites identified so far. Thus, pDolos is the first member of a new class of phage satellites, which resemble natural versions of phagemids.},
}

@article {pmid38593892,
year = {2024},
author = {Zheng, B and Wang, G and Qu, Z and Hu, J and Bao, Z and Wang, M},
title = {Glycosaminoglycan lyase: A new competition between bacteria and the pacific white shrimp Litopenaeus vannamei.},
journal = {Developmental and comparative immunology},
volume = {},
number = {},
pages = {105177},
doi = {10.1016/j.dci.2024.105177},
pmid = {38593892},
issn = {1879-0089},
abstract = {Horizontal gene transfer (HGT) is an important evolutionary force in the formation of prokaryotic and eukaryotic genomes. In recent years, many HGT genes horizontally transferred from prokaryotes to eukaryotes have been reported, and most of them are present in arthropods. The Pacific white shrimp Litopenaeus vannamei, an important economic species of arthropod, has close relationships with bacteria, providing a platform for horizontal gene transfer (HGT). In this study, we analyzed bacteria-derived HGT based on a high-quality genome of L. vannamei via a homology search and phylogenetic analysis, and six HGT genes were identified. Among these six horizontally transferred genes, we found one gene (LOC113799989) that contains a bacterial chondroitinase AC structural domain and encodes an unknown glycosaminoglycan (GAG) lyase in L. vannamei. The real-time quantitative PCR results showed that the mRNA expression level of LOC113799989 was highest in the hepatopancreas and heart, and after stimulation by Vibrio parahaemolyticus, its mRNA expression level was rapidly up-regulated within 12 h. Furthermore, after injecting si-RNA and stimulation by V. parahaemolyticus, we found that the experimental group had a higher cumulative mortality rate in 48 h than the control group, indicating that the bacteria-derived GAG lyase can reduce the mortality of shrimp with respect to infection by V. parahaemolyticus and might be related to the resistance of shrimp to bacterial diseases. Our findings contribute to the study of the function of GAGs and provide new insights into GAG-related microbial pathogenesis and host defense mechanisms in arthropods.},
}

@article {pmid38593473,
year = {2024},
author = {Paul, B and Siddaramappa, S},
title = {Comparative analysis of the diversity of trinucleotide repeats in bacterial genomes.},
journal = {Genome},
volume = {},
number = {},
pages = {},
doi = {10.1139/gen-2023-0097},
pmid = {38593473},
issn = {1480-3321},
abstract = {The human gut is the most favorable niche for microbial populations, and few studies have explored the possibilities of horizontal gene transfer between host and pathogen. Trinucleotide repeat (TNR) expansion in humans can cause more than 40 neurodegenerative diseases. Furthermore, TNRs are a type of microsatellite that resides on coding regions can contribute to the synthesis of homopolymeric amino acids. Hence, the present study aims to estimate the occurrence and diversity of TNRs in bacterial genomes available in the NCBI Genome database. Genome-wide analyses revealed that several bacterial genomes contain different types of uninterrupted TNRs. It was found that TNRs are abundant in the genomes of Alcaligenes faecalis, Mycoplasma gallisepticum, Mycoplasma genitalium, Sorangium cellulosum, and Thermus thermophilus. Interestingly, the genome of Bacillus thuringiensis strain YBT-1518 contained 169 uninterrupted ATT repeats. The genome of Leclercia adecarboxylata had 46 uninterrupted CAG repeats, which potentially translate into polyglutamine. In some instances, the TNRs were present in genes that potentially encode essential functions. Similar occurrences in human genes is known to cause genetic disorders. Further analysis of the occurrence of TNRs in bacterial genomes is likely to provide a better understanding of mismatch repair, genetic disorders, host-pathogen interaction, and homopolymeric amino acids.},
}

@article {pmid38591887,
year = {2024},
author = {Ng, WL and Rego, EH},
title = {A nucleoid-associated protein is involved in the emergence of antibiotic resistance by promoting the frequent exchange of the replicative DNA polymerase in Mycobacterium smegmatis.},
journal = {mSphere},
volume = {},
number = {},
pages = {e0012224},
doi = {10.1128/msphere.00122-24},
pmid = {38591887},
issn = {2379-5042},
abstract = {UNLABELLED: Antibiotic resistance in Mycobacterium tuberculosis exclusively originates from chromosomal mutations, either during normal DNA replication or under stress, when the expression of error-prone DNA polymerases increases to repair damaged DNA. To bypass DNA lesions and catalyze error-prone DNA synthesis, translesion polymerases must be able to access the DNA, temporarily replacing the high-fidelity replicative polymerase. The mechanisms that govern polymerase exchange are not well understood, especially in mycobacteria. Here, using a suite of quantitative fluorescence imaging techniques, we discover that in Mycobacterium smegmatis, as in other bacterial species, the replicative polymerase, DnaE1, exchanges at a timescale much faster than that of DNA replication. Interestingly, this fast exchange rate depends on an actinobacteria-specific nucleoid-associated protein (NAP), Lsr2. In cells missing lsr2, DnaE1 exchanges less frequently, and the chromosome is replicated more faithfully. Additionally, in conditions that damage DNA, cells lacking lsr2 load the complex needed to bypass DNA lesions less effectively and, consistently, replicate with higher fidelity but exhibit growth defects. Together, our results show that Lsr2 promotes dynamic flexibility of the mycobacterial replisome, which is critical for robust cell growth and lesion repair in conditions that damage DNA.

IMPORTANCE: Unlike many other pathogens, Mycobacterium tuberculosis has limited ability for horizontal gene transfer, a major mechanism for developing antibiotic resistance. Thus, the mechanisms that facilitate chromosomal mutagenesis are of particular importance in mycobacteria. Here, we show that Lsr2, a nucleoid-associated protein, has a novel role in DNA replication and mutagenesis in the model mycobacterium Mycobacterium smegmatis. We find that Lsr2 promotes the fast exchange rate of the replicative DNA polymerase, DnaE1, at the replication fork and is important for the effective loading of the DnaE2-ImuA'-ImuB translesion complex. Without lsr2, M. smegmatis replicates its chromosome more faithfully and acquires resistance to rifampin at a lower rate, but at the cost of impaired survival to DNA damaging agents. Together, our work establishes Lsr2 as a potential factor in the emergence of mycobacterial antibiotic resistance.},
}

@article {pmid38591882,
year = {2024},
author = {Xing, Y and Clark, JR and Chang, JD and Zulk, JJ and Chirman, DM and Piedra, F-A and Vaughan, EE and Hernandez Santos, HJ and Patras, KA and Maresso, AW},
title = {Progress toward a vaccine for extraintestinal pathogenic E. coli (ExPEC) II: efficacy of a toxin-autotransporter dual antigen approach.},
journal = {Infection and immunity},
volume = {},
number = {},
pages = {e0044023},
doi = {10.1128/iai.00440-23},
pmid = {38591882},
issn = {1098-5522},
abstract = {Extraintestinal pathogenic Escherichia coli (ExPEC) is a leading cause of worldwide morbidity and mortality, the top cause of antimicrobial-resistant (AMR) infections, and the most frequent cause of life-threatening sepsis and urinary tract infections (UTI) in adults. The development of an effective and universal vaccine is complicated by this pathogen's pan-genome, its ability to mix and match virulence factors and AMR genes via horizontal gene transfer, an inability to decipher commensal from pathogens, and its intimate association and co-evolution with mammals. Using a pan virulome analysis of >20,000 sequenced E. coli strains, we identified the secreted cytolysin α-hemolysin (HlyA) as a high priority target for vaccine exploration studies. We demonstrate that a catalytically inactive pure form of HlyA, expressed in an autologous host using its own secretion system, is highly immunogenic in a murine host, protects against several forms of ExPEC infection (including lethal bacteremia), and significantly lowers bacterial burdens in multiple organ systems. Interestingly, the combination of a previously reported autotransporter (SinH) with HlyA was notably effective, inducing near complete protection against lethal challenge, including commonly used infection strains ST73 (CFT073) and ST95 (UTI89), as well as a mixture of 10 of the most highly virulent sequence types and strains from our clinical collection. Both HlyA and HlyA-SinH combinations also afforded some protection against UTI89 colonization in a murine UTI model. These findings suggest recombinant, inactive hemolysin and/or its combination with SinH warrant investigation in the development of an E. coli vaccine against invasive disease.},
}

@article {pmid38591037,
year = {2024},
author = {Giermasińska-Buczek, K and Gawor, J and Stefańczyk, E and Gągała, U and Żuchniewicz, K and Rekosz-Burlaga, H and Gromadka, R and Łobocka, M},
title = {Interaction of bacteriophage P1 with an epiphytic Pantoea agglomerans strain-the role of the interplay between various mobilome elements.},
journal = {Frontiers in microbiology},
volume = {15},
number = {},
pages = {1356206},
pmid = {38591037},
issn = {1664-302X},
abstract = {P1 is a model, temperate bacteriophage of the 94 kb genome. It can lysogenize representatives of the Enterobacterales order. In lysogens, it is maintained as a plasmid. We tested P1 interactions with the biocontrol P. agglomerans L15 strain to explore the utility of P1 in P. agglomerans genome engineering. A P1 derivative carrying the Tn9 (cm[R]) transposon could transfer a plasmid from Escherichia coli to the L15 cells. The L15 cells infected with this derivative formed chloramphenicol-resistant colonies. They could grow in a liquid medium with chloramphenicol after adaptation and did not contain prophage P1 but the chromosomally inserted cm[R] marker of P1 Tn9 (cat). The insertions were accompanied by various rearrangements upstream of the Tn9 cat gene promoter and the loss of IS1 (IS1L) from the corresponding region. Sequence analysis of the L15 strain genome revealed a chromosome and three plasmids of 0.58, 0.18, and 0.07 Mb. The largest and the smallest plasmid appeared to encode partition and replication incompatibility determinants similar to those of prophage P1, respectively. In the L15 derivatives cured of the largest plasmid, P1 with Tn9 could not replace the smallest plasmid even if selected. However, it could replace the smallest and the largest plasmid of L15 if its Tn9 IS1L sequence driving the Tn9 mobility was inactivated or if it was enriched with an immobile kanamycin resistance marker. Moreover, it could develop lytically in the L15 derivatives cured of both these plasmids. Clearly, under conditions of selection for P1, the mobility of the P1 selective marker determines whether or not the incoming P1 can outcompete the incompatible L15 resident plasmids. Our results demonstrate that P. agglomerans can serve as a host for bacteriophage P1 and can be engineered with the help of this phage. They also provide an example of how antibiotics can modify the outcome of horizontal gene transfer in natural environments. Numerous plasmids of Pantoea strains appear to contain determinants of replication or partition incompatibility with P1. Therefore, P1 with an immobile selective marker may be a tool of choice in curing these strains from the respective plasmids to facilitate their functional analysis.},
}

@article {pmid38587657,
year = {2024},
author = {Gidhi, A and Jha, SK and Kumar, M and Mukhopadhyay, K},
title = {The F-box protein encoding genes of the leaf-rust fungi Puccinia triticina: genome-wide identification, characterization and expression dynamics during pathogenesis.},
journal = {Archives of microbiology},
volume = {206},
number = {5},
pages = {209},
pmid = {38587657},
issn = {1432-072X},
mesh = {Phylogeny ; Puccinia ; *Basidiomycota/genetics ; *F-Box Proteins/genetics ; },
abstract = {The F-box proteins in fungi perform diverse functions including regulation of cell cycle, circadian clock, development, signal transduction and nutrient sensing. Genome-wide analysis revealed 10 F-box genes in Puccinia triticina, the causal organism for the leaf rust disease in wheat and were characterized using in silico approaches for revealing phylogenetic relationships, gene structures, gene ontology, protein properties, sequence analysis and gene expression studies. Domain analysis predicted functional domains like WD40 and LRR at C-terminus along with the obvious presence of F-box motif in N-terminus. MSA showed amino acid replacements, which might be due to nucleotide substitution during replication. Phylogenetic analysis revealed the F-box proteins with similar domains to be clustered together while some sequences were spread out in different clades, which might be due to functional diversity. The clustering of Puccinia triticina GG705409 with Triticum aestivum TaAFB4/TaAFB5 in a single clade suggested the possibilities of horizontal gene transfer during the coevolution of P. triticina and wheat. Gene ontological annotation categorized them into three classes and were functionally involved in protein degradation through the protein ubiquitination pathway. Protein-protein interaction network revealed F-box proteins to interact with other components of the SCF complex involved in protein ubiquitination. Relative expression analysis of five F-box genes in a time course experiment denoted their involvement in leaf rust susceptible wheat plants. This study provides information on structure elucidation of F-box proteins of a basidiomycetes plant pathogenic fungi and their role during pathogenesis.},
}

Phylogeny
Puccinia
*Basidiomycota/genetics
*F-Box Proteins/genetics

@article {pmid38587426,
year = {2024},
author = {Bessen, DE and Beall, BW and Hayes, A and Huang, W and DiChiara, JM and Velusamy, S and Tettelin, H and Jolley, KA and Fallon, JT and Chochua, S and Alobaidallah, MSA and Higgs, C and Barnett, TC and Steemson, JT and Proft, T and Davies, MR},
title = {Recombinational exchange of M-fibril and T-pilus genes generates extensive cell surface diversity in the global group A Streptococcus population.},
journal = {mBio},
volume = {},
number = {},
pages = {e0069324},
doi = {10.1128/mbio.00693-24},
pmid = {38587426},
issn = {2150-7511},
abstract = {Among genes present in all group A streptococci (GAS), those encoding M-fibril and T-pilus proteins display the highest levels of sequence diversity, giving rise to the two primary serological typing schemes historically used to define strain. A new genotyping scheme for the pilin adhesin and backbone genes is developed and, when combined with emm typing, provides an account of the global GAS strain population. Cluster analysis based on nucleotide sequence similarity assigns most T-serotypes to discrete pilin backbone sequence clusters, yet the established T-types correspond to only half the clusters. The major pilin adhesin and backbone sequence clusters yield 98 unique combinations, defined as "pilin types." Numerous horizontal transfer events that involve pilin or emm genes generate extensive antigenic and functional diversity on the bacterial cell surface and lead to the emergence of new strains. Inferred pilin genotypes applied to a meta-analysis of global population-based collections of pharyngitis and impetigo isolates reveal highly significant associations between pilin genotypes and GAS infection at distinct ecological niches, consistent with a role for pilin gene products in adaptive evolution. Integration of emm and pilin typing into open-access online tools (pubmlst.org) ensures broad utility for end-users wanting to determine the architecture of M-fibril and T-pilus genes from genome assemblies.IMPORTANCEPrecision in defining the variant forms of infectious agents is critical to understanding their population biology and the epidemiology of associated diseases. Group A Streptococcus (GAS) is a global pathogen that causes a wide range of diseases and displays a highly diverse cell surface due to the antigenic heterogeneity of M-fibril and T-pilus proteins which also act as virulence factors of varied functions. emm genotyping is well-established and highly utilized, but there is no counterpart for pilin genes. A global GAS collection provides the basis for a comprehensive pilin typing scheme, and online tools for determining emm and pilin genotypes are developed. Application of these tools reveals the expansion of structural-functional diversity among GAS via horizontal gene transfer, as evidenced by unique combinations of surface protein genes. Pilin and emm genotype correlations with superficial throat vs skin infection provide new insights on the molecular determinants underlying key ecological and epidemiological trends.},
}

@article {pmid38585972,
year = {2024},
author = {Marin, MG and Wippel, C and Quinones-Olvera, N and Behruznia, M and Jeffrey, BM and Harris, M and Mann, BC and Rosenthal, A and Jacobson, KR and Warren, RM and Li, H and Meehan, CJ and Farhat, MR},
title = {Analysis of the limited M. tuberculosis accessory genome reveals potential pitfalls of pan-genome analysis approaches.},
journal = {bioRxiv : the preprint server for biology},
volume = {},
number = {},
pages = {},
doi = {10.1101/2024.03.21.586149},
pmid = {38585972},
abstract = {Pan-genome analysis is a fundamental tool in the study of bacterial genome evolution. Benchmarking the accuracy of pan-genome analysis methods is challenging, because it can be significantly influenced by both the methodology used to compare genomes, as well as differences in the accuracy and representativeness of the genomes analyzed. In this work, we curated a collection of 151 Mycobacterium tuberculosis (Mtb) isolates to evaluate sources of variability in pan-genome analysis. Mtb is characterized by its clonal evolution, absence of horizontal gene transfer, and limited accessory genome, making it an ideal test case for this study. Using a state-of-the-art graph-genome approach, we found that a majority of the structural variation observed in Mtb originates from rearrangement, deletion, and duplication of redundant nucleotide sequences. In contrast, we found that pan-genome analyses that focus on comparison of coding sequences (at the amino acid level) can yield surprisingly variable results, driven by differences in assembly quality and the softwares used. Upon closer inspection, we found that coding sequence annotation discrepancies were a major contributor to inflated Mtb accessory genome estimates. To address this, we developed panqc, a software that detects annotation discrepancies and collapses nucleotide redundancy in pan-genome estimates. We characterized the effect of the panqc adjustment on both pan-genome analysis of Mtb and E. coli genomes, and highlight how different levels of genomic diversity are prone to unique biases. Overall, this study illustrates the need for careful methodological selection and quality control to accurately map the evolutionary dynamics of a bacterial species.},
}

@article {pmid38585963,
year = {2024},
author = {Maier, JL and Gin, C and Callahan, B and Sheriff, EK and Duerkop, BA and Kleiner, M},
title = {Pseudo-pac site sequences used by phage P22 in generalized transduction of Salmonella.},
journal = {bioRxiv : the preprint server for biology},
volume = {},
number = {},
pages = {},
doi = {10.1101/2024.03.25.586692},
pmid = {38585963},
abstract = {UNLABELLED: Salmonella enterica Serovar Typhimurium (Salmonella) and its bacteriophage P22 are a model system for the study of horizontal gene transfer by generalized transduction. Typically, the P22 DNA packaging machinery initiates packaging when a short sequence of DNA, known as the pac site, is recognized on the P22 genome. However, sequences similar to the pac site in the host genome, called pseudo-pac sites, lead to erroneous packaging and subsequent generalized transduction of Salmonella DNA. While the general genomic locations of the Salmonella pseudo-pac sites are known, the sequences themselves have not been determined. We used visualization of P22 sequencing reads mapped to host Salmonella genomes to define regions of generalized transduction initiation and the likely locations of pseudo-pac sites. We searched each genome region for the sequence with the highest similarity to the P22 pac site and aligned the resulting sequences. We built a regular expression (sequence match pattern) from the alignment and used it to search the genomes of two P22-susceptible Salmonella strains-LT2 and 14028S- for sequence matches. The final regular expression successfully identified pseudo-pac sites in both LT2 and 14028S that correspond with generalized transduction initiation sites in mapped read coverages. The pseudo-pac site sequences identified in this study can be used to predict locations of generalized transduction in other P22-susceptible hosts or to initiate generalized transduction at specific locations in P22-susceptible hosts with genetic engineering. Furthermore, the bioinformatics approach used to identify the Salmonella pseudo-pac sites in this study could be applied to other phage-host systems.

IMPORTANCE: Bacteriophage P22 has been a genetic tool and a key model for the study of generalized transduction in Salmonella since the 1950s, yet certain components of the generalized transduction molecular mechanism remain unknown. Specifically, the locations and sequences of pseudo-pac sites, hypothesized to facilitate packaging of Salmonella DNA by P22, to date have not been determined. In this study, we identified the specific locations and sequences of the pseudo-pac sites frequently recognized by P22 in Salmonella genomes. The identification of highly efficient pseudo-pac sites in Salmonella provides fundamental insights into the sequence specificity necessary for P22 pac site recognition and opens the door to more targeted use of generalized transduction with P22.},
}

@article {pmid38579360,
year = {2024},
author = {Whitfield, GB and Brun, YV},
title = {The type IVc pilus: just a Tad different.},
journal = {Current opinion in microbiology},
volume = {79},
number = {},
pages = {102468},
doi = {10.1016/j.mib.2024.102468},
pmid = {38579360},
issn = {1879-0364},
abstract = {Bacteria utilize type IV pili (T4P) to interact with their environment, where they facilitate processes including motility, adherence, and DNA uptake. T4P require multisubunit, membrane-spanning nanomachines for assembly. The tight adherence (Tad) pili are an Archaea-derived T4P subgroup whose machinery exhibits significant mechanistic and architectural differences from bacterial type IVa and IVb pili. Most Tad biosynthetic genes are encoded in a single locus that is widespread in bacteria due to facile acquisition via horizontal gene transfer. These loci experience extensive structural rearrangements, including the acquisition of novel regulatory or biosynthetic genes, which fine-tune their function. This has permitted their integration into many different bacterial lifestyles, including the Caulobacter crescentus cell cycle, Myxococcus xanthus predation, and numerous plant and mammalian pathogens and symbionts.},
}

@article {pmid38578105,
year = {2024},
author = {Darby, EM and Moran, RA and Holden, E and Morris, T and Harrison, F and Clough, B and McInnes, RS and Schneider, L and Frickel, EM and Webber, MA and Blair, JMA},
title = {Differential development of antibiotic resistance and virulence between Acinetobacter species.},
journal = {mSphere},
volume = {},
number = {},
pages = {e0010924},
doi = {10.1128/msphere.00109-24},
pmid = {38578105},
issn = {2379-5042},
abstract = {UNLABELLED: The two species that account for most cases of Acinetobacter-associated bacteremia in the United Kingdom are Acinetobacter lwoffii, often a commensal but also an emerging pathogen, and Acinetobacter baumannii, a well-known antibiotic-resistant species. While these species both cause similar types of human infection and occupy the same niche, A. lwoffii (unlike A. baumannii) has thus far remained susceptible to antibiotics. Comparatively little is known about the biology of A. lwoffii, and this is the largest study on it conducted to date, providing valuable insights into its behaviour and potential threat to human health. This study aimed to explain the antibiotic susceptibility, virulence, and fundamental biological differences between these two species. The relative susceptibility of A. lwoffii was explained as it encoded fewer antibiotic resistance and efflux pump genes than A. baumannii (9 and 30, respectively). While both species had markers of horizontal gene transfer, A. lwoffii encoded more DNA defense systems and harbored a far more restricted range of plasmids. Furthermore, A. lwoffii displayed a reduced ability to select for antibiotic resistance mutations, form biofilm, and infect both in vivo and in in vitro models of infection. This study suggests that the emerging pathogen A. lwoffii has remained susceptible to antibiotics because mechanisms exist to make it highly selective about the DNA it acquires, and we hypothesize that the fact that it only harbors a single RND system restricts the ability to select for resistance mutations. This provides valuable insights into how development of resistance can be constrained in Gram-negative bacteria.

IMPORTANCE: Acinetobacter lwoffii is often a harmless commensal but is also an emerging pathogen and is the most common cause of Acinetobacter-derived bloodstream infections in England and Wales. In contrast to the well-studied and often highly drug-resistant A. baumannii, A. lwoffii has remained susceptible to antibiotics. This study explains why this organism has not evolved resistance to antibiotics. These new insights are important to understand why and how some species develop antibiotic resistance, while others do not, and could inform future novel treatment strategies.},
}

@article {pmid38574109,
year = {2024},
author = {Samson, S and Lord, É and Makarenkov, V},
title = {Assessing the emergence time of SARS-CoV-2 zoonotic spillover.},
journal = {PloS one},
volume = {19},
number = {4},
pages = {e0301195},
pmid = {38574109},
issn = {1932-6203},
mesh = {Animals ; Humans ; SARS-CoV-2/genetics ; Phylogeny ; *Chiroptera ; Pangolins/genetics ; *COVID-19/epidemiology ; Bayes Theorem ; Zoonoses/epidemiology ; },
abstract = {Understanding the evolution of Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV-2) and its relationship to other coronaviruses in the wild is crucial for preventing future virus outbreaks. While the origin of the SARS-CoV-2 pandemic remains uncertain, mounting evidence suggests the direct involvement of the bat and pangolin coronaviruses in the evolution of the SARS-CoV-2 genome. To unravel the early days of a probable zoonotic spillover event, we analyzed genomic data from various coronavirus strains from both human and wild hosts. Bayesian phylogenetic analysis was performed using multiple datasets, using strict and relaxed clock evolutionary models to estimate the occurrence times of key speciation, gene transfer, and recombination events affecting the evolution of SARS-CoV-2 and its closest relatives. We found strong evidence supporting the presence of temporal structure in datasets containing SARS-CoV-2 variants, enabling us to estimate the time of SARS-CoV-2 zoonotic spillover between August and early October 2019. In contrast, datasets without SARS-CoV-2 variants provided mixed results in terms of temporal structure. However, they allowed us to establish that the presence of a statistically robust clade in the phylogenies of gene S and its receptor-binding (RBD) domain, including two bat (BANAL) and two Guangdong pangolin coronaviruses (CoVs), is due to the horizontal gene transfer of this gene from the bat CoV to the pangolin CoV that occurred in the middle of 2018. Importantly, this clade is closely located to SARS-CoV-2 in both phylogenies. This phylogenetic proximity had been explained by an RBD gene transfer from the Guangdong pangolin CoV to a very recent ancestor of SARS-CoV-2 in some earlier works in the field before the BANAL coronaviruses were discovered. Overall, our study provides valuable insights into the timeline and evolutionary dynamics of the SARS-CoV-2 pandemic.},
}

Animals
Humans
SARS-CoV-2/genetics
Phylogeny
*Chiroptera
Pangolins/genetics
*COVID-19/epidemiology
Bayes Theorem
Zoonoses/epidemiology

@article {pmid38572613,
year = {2024},
author = {Moore, KA and Petersen, AP and Zierden, HC},
title = {Microorganism-derived extracellular vesicles: emerging contributors to female reproductive health.},
journal = {Nanoscale},
volume = {},
number = {},
pages = {},
doi = {10.1039/d3nr05524h},
pmid = {38572613},
issn = {2040-3372},
abstract = {Extracellular vesicles (EVs) are cell-derived nanoparticles that carry small molecules, nucleic acids, and proteins long distances in the body facilitating cell-cell communication. Microorganism-derived EVs mediate communication between parent cells and host cells, with recent evidence supporting their role in biofilm formation, horizontal gene transfer, and suppression of the host immune system. As lipid-bound bacterial byproducts, EVs demonstrate improved cellular uptake and distribution in vivo compared to cell-free nucleic acids, proteins, or small molecules, allowing these biological nanoparticles to recapitulate the effects of parent cells and contribute to a range of human health outcomes. Here, we focus on how EVs derived from vaginal microorganisms contribute to gynecologic and obstetric outcomes. As the composition of the vaginal microbiome significantly impacts women's health, we discuss bacterial EVs from both healthy and dysbiotic vaginal microbiota. We also examine recent work done to evaluate the role of EVs from common vaginal bacterial, fungal, and parasitic pathogens in pathogenesis of female reproductive tract disease. We highlight evidence for the role of EVs in women's health, gaps in current knowledge, and opportunities for future work. Finally, we discuss how leveraging the innate interactions between microorganisms and mammalian cells may establish EVs as a novel therapeutic modality for gynecologic and obstetric indications.},
}

@article {pmid38568420,
year = {2024},
author = {Hamrick, GS and Maddamsetti, R and Son, HI and Wilson, ML and Davis, HM and You, L},
title = {Programming Dynamic Division of Labor Using Horizontal Gene Transfer.},
journal = {ACS synthetic biology},
volume = {},
number = {},
pages = {},
doi = {10.1021/acssynbio.3c00615},
pmid = {38568420},
issn = {2161-5063},
abstract = {The metabolic engineering of microbes has broad applications, including biomanufacturing, bioprocessing, and environmental remediation. The introduction of a complex, multistep pathway often imposes a substantial metabolic burden on the host cell, restraining the accumulation of productive biomass and limiting pathway efficiency. One strategy to alleviate metabolic burden is the division of labor (DOL) in which different subpopulations carry out different parts of the pathway and work together to convert a substrate into a final product. However, the maintenance of different engineered subpopulations is challenging due to competition and convoluted interstrain population dynamics. Through modeling, we show that dynamic division of labor (DDOL), which we define as the DOL between indiscrete populations capable of dynamic and reversible interchange, can overcome these limitations and enable the robust maintenance of burdensome, multistep pathways. We propose that DDOL can be mediated by horizontal gene transfer (HGT) and use plasmid genomics to uncover evidence that DDOL is a strategy utilized by natural microbial communities. Our work suggests that bioengineers can harness HGT to stabilize synthetic metabolic pathways in microbial communities, enabling the development of robust engineered systems for deployment in a variety of contexts.},
}

@article {pmid38568247,
year = {2024},
author = {Fu, S and Iqbal, B and Li, G and Alabbosh, KF and Khan, KA and Zhao, X and Raheem, A and Du, D},
title = {The role of microbial partners in heavy metal metabolism in plants: a review.},
journal = {Plant cell reports},
volume = {43},
number = {4},
pages = {111},
pmid = {38568247},
issn = {1432-203X},
support = {BK20220030//Open Project of the Carbon Peak and Carbon Neutrality Technology Innovation Foundation of Jiangsu Province/ ; 32271587//National Natural Science Foundation of China/ ; 3235041400//National Natural Science Foundation of China/ ; 18JDG039//Senior Talent Foundation of Jiangsu University/ ; RGP2/360/44//Deanship of Scientific Research at King Khalid University Saudi Arabia for funding this work through Large Groups Project/ ; },
mesh = {*Herb-Drug Interactions ; *Metals, Heavy/toxicity ; Protein Processing, Post-Translational ; Soil ; },
abstract = {Heavy metal pollution threatens plant growth and development as well as ecological stability. Here, we synthesize current research on the interplay between plants and their microbial symbionts under heavy metal stress, highlighting the mechanisms employed by microbes to enhance plant tolerance and resilience. Several key strategies such as bioavailability alteration, chelation, detoxification, induced systemic tolerance, horizontal gene transfer, and methylation and demethylation, are examined, alongside the genetic and molecular basis governing these plant-microbe interactions. However, the complexity of plant-microbe interactions, coupled with our limited understanding of the associated mechanisms, presents challenges in their practical application. Thus, this review underscores the necessity of a more detailed understanding of how plants and microbes interact and the importance of using a combined approach from different scientific fields to maximize the benefits of these microbial processes. By advancing our knowledge of plant-microbe synergies in the metabolism of heavy metals, we can develop more effective bioremediation strategies to combat the contamination of soil by heavy metals.},
}

*Herb-Drug Interactions
*Metals, Heavy/toxicity
Protein Processing, Post-Translational
Soil

@article {pmid38565359,
year = {2024},
author = {Medeiros, P and Canato, D and Sergio Kimus Braz, A and Campos Paulino, L},
title = {Phylogenetic analyses reveal insights into interdomain horizontal gene transfer of microbial lipases.},
journal = {Molecular phylogenetics and evolution},
volume = {},
number = {},
pages = {108069},
doi = {10.1016/j.ympev.2024.108069},
pmid = {38565359},
issn = {1095-9513},
abstract = {Microbial lipases play a pivotal role in a wide range of biotechnological processes and in the human skin microbiome. However, their evolution remains poorly understood. Accessing the evolutionary process of lipases could contribute to future applications in health and biotechnology. We investigated genetic events associated with the evolutionary trajectory of the microbial family LIP lipases. Using phylogenetic analysis, we identified two distinct horizontal gene transfer (HGT) events from Bacteria to Fungi. Further analysis of human cutaneous mycobiome members such as the lipophilic Malassezia yeasts and CUG-Ser-1 clade (including Candida sp. and other microorganisms associated with cutaneous mycobiota) revealed recent evolutionary processes, with multiple gene duplication events. The Lid region of fungal lipases, crucial for substrate interaction, exhibits varying degrees of conservation among different groups. Our findings suggest the adaptability of the fungal LIP family in various genetic and metabolic contexts and its potential role in niche exploration.},
}

@article {pmid38415983,
year = {2024},
author = {Zhang, M and Yang, B and Shi, J and Wang, Z and Liu, Y},
title = {Host defense peptides mitigate the spread of antibiotic resistance in physiologically relevant condition.},
journal = {Antimicrobial agents and chemotherapy},
volume = {68},
number = {4},
pages = {e0126123},
doi = {10.1128/aac.01261-23},
pmid = {38415983},
issn = {1098-6596},
support = {32222084, 32172907//MOST | National Natural Science Foundation of China (NSFC)/ ; },
mesh = {Animals ; Cattle ; Humans ; *Conjugation, Genetic ; Plasmids/genetics ; Drug Resistance, Microbial ; *Genes, Bacterial ; Gene Transfer, Horizontal ; Antimicrobial Cationic Peptides/pharmacology ; Anti-Bacterial Agents/pharmacology ; },
abstract = {Antibiotic resistance represents a significant challenge to public health and human safety. The primary driver behind the dissemination of antibiotic resistance is the horizontal transfer of plasmids. Current conjugative transfer assay is generally performed in a standardized manner, ignoring the effect of the host environment. Host defense peptides (HDPs) possess a wide range of biological targets and play an essential role in the innate immune system. Herein, we reveal that sub-minimum inhibitory concentrations of HDPs facilitate the conjugative transfer of RP4-7 plasmid in the Luria Broth medium, and this observation is reversed in the RPMI medium, designed to simulate the host environment. Out of these HDPs, indolicidin (Ind), a cationic tridecapeptide from bovine neutrophils, significantly inhibits the conjugation of multidrug resistance plasmids in a dose-dependent manner, including blaNDM- and tet(X4)-bearing plasmids. We demonstrate that the addition of Ind to RPMI medium as the incubation substrate downregulates the expression of conjugation-related genes. In addition, Ind weakens the tricarboxylic acid cycle, impedes the electron transport chain, and disrupts the proton motive force, consequently diminishing the synthesis of adenosine triphosphate and limiting the energy supply. Our findings highlight the importance of the host-like environments for the development of horizontal transfer inhibitors and demonstrate the potential of HDPs in preventing the spread of resistance plasmids.},
}

Animals
Cattle
Humans
*Conjugation, Genetic
Plasmids/genetics
Drug Resistance, Microbial
*Genes, Bacterial
Gene Transfer, Horizontal
Antimicrobial Cationic Peptides/pharmacology
Anti-Bacterial Agents/pharmacology

@article {pmid38565354,
year = {2024},
author = {Li, X and Chen, T and Ren, Q and Lu, J and Cao, S and Liu, C and Li, Y},
title = {Phages in sludge from the A/O wastewater treatment process play an important role in the transmission of ARGs.},
journal = {The Science of the total environment},
volume = {},
number = {},
pages = {172111},
doi = {10.1016/j.scitotenv.2024.172111},
pmid = {38565354},
issn = {1879-1026},
abstract = {Phages can influence the horizontal gene transfer (HGT) of antibiotic resistance genes (ARGs) through transduction, but their profiles and effects on the transmission of ARGs are unclear, especially in complex swine sludge. In this study, we investigated the characterization of phage and ARG profiles in sludge generated from anoxic/oxic (A/O) wastewater treatment processes on swine farms using metagenomes and viromes. The results demonstrated that 205-221 subtypes of ARGs could be identified in swine sludge, among which sul1, tet(M), and floR were the dominant ARGs, indicating that sludge is an important reservoir of ARGs, especially in sludge tanks. The greater abundance of mobile genetic elements (MGEs) in the sludge (S) could be a significant factor regarding the greater abundance of ARGs in the sludge than in the anoxic (A) and oxic (O) tanks (P < 0.05). However, when we compared the abundances of ARGs and MGEs in the A and O tanks, we observed opposite significant differences (P < 0.05), suggesting that MGEs are not the only factor influencing the abundance of ARGs. The high proportion of lysogenic phages in sludge from the S tank can also have a major impact on the ARG profile. Siphoviridae, Myoviridae, and Podoviridae were the dominant phage families in sludge, and a network diagram of bacteria-ARG-phages revealed that dominant phages and bacteria acted simultaneously as potential hosts for ARGs, which may have led to phage-mediated HGT of ARGs. Therefore, the risk of phage-mediated HGT of ARGs cannot be overlooked.},
}

@article {pmid38564675,
year = {2024},
author = {Lehman, SS and Verhoeve, VI and Driscoll, TP and Beckmann, JF and Gillespie, JJ},
title = {Metagenome diversity illuminates the origins of pathogen effectors.},
journal = {mBio},
volume = {},
number = {},
pages = {e0075923},
doi = {10.1128/mbio.00759-23},
pmid = {38564675},
issn = {2150-7511},
abstract = {Recent metagenome-assembled genome (MAG) analyses have profoundly impacted Rickettsiology systematics. The discovery of basal lineages (novel families Mitibacteraceae and Athabascaceae) with predicted extracellular lifestyles exposed an evolutionary timepoint for the transition to host dependency, which seemingly occurred independent of mitochondrial evolution. Notably, these basal rickettsiae carry the Rickettsiales vir homolog (rvh) type IV secretion system and purportedly use rvh to kill congener microbes rather than parasitize host cells as described for later-evolving rickettsial pathogens. MAG analysis also substantially increased diversity for the genus Rickettsia and delineated a sister lineage (the novel genus Tisiphia) that stands to inform on the emergence of human pathogens from protist and invertebrate endosymbionts. Herein, we probed Rickettsiales MAG and genomic diversity for the distribution of Rickettsia rvh effectors to ascertain their origins. A sparse distribution of most Rickettsia rvh effectors outside of Rickettsiaceae lineages illuminates unique rvh evolution from basal extracellular species and other rickettsial families. Remarkably, nearly every effector was found in multiple divergent forms with variable architectures, indicating profound roles for gene duplication and recombination in shaping effector repertoires in Rickettsia pathogens. Lateral gene transfer plays a prominent role in shaping the rvh effector landscape, as evinced by the discovery of many effectors on plasmids and conjugative transposons, as well as pervasive effector gene exchange between Rickettsia and Legionella species. Our study exemplifies how MAGs can yield insight into pathogen effector origins, particularly how effector architectures might become tailored to the discrete host cell functions of different eukaryotic hosts.IMPORTANCEWhile rickettsioses are deadly vector-borne human diseases, factors distinguishing Rickettsia pathogens from the innumerable bevy of environmental rickettsial endosymbionts remain lacking. Recent metagenome-assembled genome (MAG) studies revealed evolutionary timepoints for rickettsial transitions to host dependency. The rvh type IV secretion system was likely repurposed from congener killing in basal extracellular species to parasitizing host cells in later-evolving pathogens. Our analysis of MAG diversity for over two dozen rvh effectors unearthed their presence in some non-pathogens. However, most effectors were found in multiple divergent forms with variable architectures, indicating gene duplication and recombination-fashioned effector repertoires of Rickettsia pathogens. Lateral gene transfer substantially shaped pathogen effector arsenals, evinced by the discovery of effectors on plasmids and conjugative transposons, as well as pervasive effector gene exchanges between Rickettsia and Legionella species. Our study exemplifies how MAGs yield insight into pathogen effector origins and evolutionary processes tailoring effectors to eukaryotic host cell biology.},
}

@article {pmid38561802,
year = {2024},
author = {Lanoizelet, M and Elkhoury Youhanna, C and Roure, A and Darras, S},
title = {Molecular control of cellulosic fin morphogenesis in ascidians.},
journal = {BMC biology},
volume = {22},
number = {1},
pages = {74},
pmid = {38561802},
issn = {1741-7007},
support = {Emergence 2021//Sorbonne Université/ ; DBM2020//Institut des sciences biologiques/ ; DBM2022//Institut des sciences biologiques/ ; },
abstract = {BACKGROUND: The tunicates form a group of filter-feeding marine animals closely related to vertebrates. They share with them a number of features such as a notochord and a dorsal neural tube in the tadpole larvae of ascidians, one of the three groups that make tunicates. However, a number of typical chordate characters have been lost in different branches of tunicates, a diverse and fast-evolving phylum. Consequently, the tunic, a sort of exoskeleton made of extracellular material including cellulose secreted by the epidermis, is the unifying character defining the tunicate phylum. In the larva of ascidians, the tunic differentiates in the tail into a median fin (with dorsal and ventral extended blades) and a caudal fin.

RESULTS: Here we have performed experiments in the ascidian Phallusia mammillata to address the molecular control of tunic 3D morphogenesis. We have demonstrated that the tail epidermis medio-lateral patterning essential for peripheral nervous system specification also controls tunic elongation into fins. More specifically, when tail epidermis midline identity was abolished by BMP signaling inhibition, or CRISPR/Cas9 inactivation of the transcription factor coding genes Msx or Klf1/2/4/17, median fin did not form. We postulated that this genetic program should regulate effectors of tunic secretion. We thus analyzed the expression and regulation in different ascidian species of two genes acquired by horizontal gene transfer (HGT) from bacteria, CesA coding for a cellulose synthase and Gh6 coding for a cellulase. We have uncovered an unexpected dynamic history of these genes in tunicates and high levels of variability in gene expression and regulation among ascidians. Although, in Phallusia, Gh6 has a regionalized expression in the epidermis compatible with an involvement in fin elongation, our functional studies indicate a minor function during caudal fin formation only.

CONCLUSIONS: Our study constitutes an important step in the study of the integration of HGT-acquired genes into developmental networks and a cellulose-based morphogenesis of extracellular material in animals.},
}

@article {pmid38561223,
year = {2024},
author = {LeBleu, VS and Kanasaki, K and Lovisa, S and Alge, JL and Kim, J and Chen, Y and Teng, Y and Gerami-Naini, B and Sugimoto, H and Kato, N and Revuelta, I and Grau, N and Sleeman, JP and Taduri, G and Kizu, A and Rafii, S and Hochedlinger, K and Quaggin, SE and Kalluri, R},
title = {Genetic reprogramming with stem cells regenerates glomerular epithelial podocytes in Alport syndrome.},
journal = {Life science alliance},
volume = {7},
number = {6},
pages = {},
doi = {10.26508/lsa.202402664},
pmid = {38561223},
issn = {2575-1077},
abstract = {Glomerular filtration relies on the type IV collagen (ColIV) network of the glomerular basement membrane, namely, in the triple helical molecules containing the α3, α4, and α5 chains of ColIV. Loss of function mutations in the genes encoding these chains (Col4a3, Col4a4, and Col4a5) is associated with the loss of renal function observed in Alport syndrome (AS). Precise understanding of the cellular basis for the patho-mechanism remains unknown and a specific therapy for this disease does not currently exist. Here, we generated a novel allele for the conditional deletion of Col4a3 in different glomerular cell types in mice. We found that podocytes specifically generate α3 chains in the developing glomerular basement membrane, and that its absence is sufficient to impair glomerular filtration as seen in AS. Next, we show that horizontal gene transfer, enhanced by TGFβ1 and using allogenic bone marrow-derived mesenchymal stem cells and induced pluripotent stem cells, rescues Col4a3 expression and revive kidney function in Col4a3-deficient AS mice. Our proof-of-concept study supports that horizontal gene transfer such as cell fusion enables cell-based therapy in Alport syndrome.},
}

@article {pmid38560215,
year = {2024},
author = {Comba-González, NB and Chaves-Moreno, D and Santamaría-Vanegas, J and Montoya-Castaño, D},
title = {A pan-genomic assessment: Delving into the genome of the marine epiphyte Bacillus altitudinis strain 19_A and other very close Bacillus strains from multiple environments.},
journal = {Heliyon},
volume = {10},
number = {7},
pages = {e27820},
pmid = {38560215},
issn = {2405-8440},
abstract = {Marine macroalgae are the habitat of epiphytic bacteria and provide several conditions for a beneficial biological interaction to thrive. Although Bacillus is one of the most abundant epiphytic genera, genomic information on marine macroalgae-associated Bacillus species remains scarce. In this study, we further investigated our previously published genome of the epiphytic strain Bacillus altitudinis 19_A to find features that could be translated to potential metabolites produced by this microorganism, as well as genes that play a role in its interaction with its macroalgal host. To achieve this goal, we performed a pan-genome analysis of Bacillus sp. and a codon bias assessment, including the genome of the strain Bacillus altitudinis 19_A and 29 complete genome sequences of closely related Bacillus strains isolated from soil, marine environments, plants, extreme environments, air, and food. This genomic analysis revealed that Bacillus altitudinis 19_A possessed unique genes encoding proteins involved in horizontal gene transfer, DNA repair, transcriptional regulation, and bacteriocin biosynthesis. In this comparative analysis, codon bias was not associated with the habitat of the strains studied. Some accessory genes were identified in the Bacillus altitudinis 19_A genome that could be related to its epiphytic lifestyle, as well as gene clusters for the biosynthesis of a sporulation-killing factor and a bacteriocin, showing their potential as a source of antimicrobial peptides. Our results provide a comprehensive view of the Bacillus altitudinis 19_A genome to understand its adaptation to the marine environment and its potential as a producer of bioactive compounds.},
}

@article {pmid38555673,
year = {2024},
author = {Sun, H and Chang, H and Zhu, Y and Li, X and Yang, X and Zhou, X and Wu, D and Ding, J and Liu, Y},
title = {Strong suppression of silver nanoparticles on antibiotic resistome in anammox process.},
journal = {Journal of hazardous materials},
volume = {470},
number = {},
pages = {134128},
doi = {10.1016/j.jhazmat.2024.134128},
pmid = {38555673},
issn = {1873-3336},
abstract = {This study comprehensively deciphered the effect of silver nanoparticles (AgNPs) on anammox flocculent sludge, including nitrogen removal performance, microbial community structure, functional enzyme abundance, antibiotic resistance gene (ARGs) dissemination, and horizontal gene transfer (HGT) mechanisms. After long-term exposure to 0-2.5 mg/L AgNPs for 200 cycles, anammox performance significantly decreased (P < 0.05), while the relative abundances of dominant Ca. Kuenenia and anammox-related enzymes (hzsA, nirK) increased compared to the control (P < 0.05). For antibiotic resistome, ARG abundance hardly changed with 0-0.5 mg/L AgNPs but decreased by approximately 90% with 1.5-2.5 mg/L AgNPs. More importantly, AgNPs effectively inhibited MGE-mediated HGT of ARGs. Additionally, structural equation model (SEM) disclosed the underlying relationship between AgNPs, the antibiotic resistome, and the microbial community. Overall, AgNPs suppressed the anammox-driven nitrogen cycle, regulated the microbial community, and prevented the spread of ARGs in anammox flocs. This study provides a theoretical baseline for an advanced understanding of the ecological roles of nanoparticles and resistance elements in engineered ecosystems.},
}

@article {pmid38554973,
year = {2024},
author = {Song, H and Yoo, JS and Unno, T},
title = {Discerning the dissemination mechanisms of antibiotic resistance genes through whole genome sequencing of extended-spectrum beta-lactamase (ESBL)-producing E. coli isolated from veterinary clinics and farms in South Korea.},
journal = {The Science of the total environment},
volume = {},
number = {},
pages = {172068},
doi = {10.1016/j.scitotenv.2024.172068},
pmid = {38554973},
issn = {1879-1026},
abstract = {Extended-spectrum beta-lactamase (ESBL)-producing bacteria are resistant to most beta-lactams, including third-generation cephalosporins, limiting the treatment methods against the infections they cause. In this study, we performed whole genome sequencing of ESBL-producing E. coli to determine the mechanisms underlying the dissemination of antibiotic resistance genes. We analyzed 141 ESBL-producing isolates which had been collected from 16 veterinary clinics and 16 farms in South Korea. Long- and short-read sequencing platforms were used to obtain high-quality assemblies. The results showed that blaCTX-M is the dominant ESBL gene type found in South Korea. The spread of blaCTX-M appears to have been facilitated by both clonal spread between different host species and conjugation. Most blaCTX-M genes were found associated with diverse mobile genetic elements that may contribute to the chromosomal integration of the genes. Diverse incompatibility groups of blaCTX-M-harboring plasmids were also observed, which allows their spread among a variety of bacteria. Comprehensive whole genome sequence analysis was useful for the identification of the most prevalent types of ESBL genes and their dissemination mechanisms. The results of this study suggest that the propagation of ESBL genes can occur through clonal spread and plasmid-mediated dissemination, and that suitable action plans should be developed to prevent further propagation of these genes.},
}

@article {pmid38554512,
year = {2024},
author = {Qin, J and Qi, X and Li, Y and Tang, Z and Zhang, X and Ru, S and Xiong, JQ},
title = {Bisphenols can promote antibiotic resistance by inducing metabolic adaptations and natural transformation.},
journal = {Journal of hazardous materials},
volume = {470},
number = {},
pages = {134149},
doi = {10.1016/j.jhazmat.2024.134149},
pmid = {38554512},
issn = {1873-3336},
abstract = {Whether bisphenols, as plasticizers, can influence bacterial uptake of antibiotic resistance genes (ARGs) in natural environment, as well as the underlying mechanism remains largely unknown. Our results showed that four commonly used bisphenols (bisphenol A, S, F, and AF) at their environmental relative concentrations can significantly promote transmission of ARGs by 2.97-3.56 times in Acinetobacter baylyi ADP1. Intriguingly, we observed ADP1 acquired resistance by integrating plasmids uptake and cellular metabolic adaptations other than through reactive oxygen species mediated pathway. Metabolic adaptations including upregulation of capsules polysaccharide biosynthesis and intracellularly metabolic enzymes, which enabled formation of thicker capsules for capturing free plasmids, and degradation of accumulated compounds. Simultaneously, genes encoding DNA uptake and translocation machinery were incorporated to enhance natural transformation of antibiotic resistance carrying plasmids. We further exposed aquatic fish to bisphenols for 120 days to monitor their long-term effects in aquatic environment, which showed that intestinal bacteria communities were dominated by a drug resistant microbiome. Our study provides new insight into the mechanism of enhanced natural transformation of ARGs by bisphenols, and highlights the investigations for unexpectedly-elevated antibiotic-resistant risks by structurally related environmental chemicals.},
}

@article {pmid38552150,
year = {2024},
author = {Howard-Varona, C and Lindback, MM and Fudyma, JD and Krongauz, A and Solonenko, NE and Zayed, AA and Andreopoulos, WB and Olson, HM and Kim, YM and Kyle, JE and Del Rio, TG and Adkins, JN and Tfaily, MM and Paul, S and Sullivan, MB and Duhaime, MB},
title = {Environment-specific virocell metabolic reprogramming.},
journal = {The ISME journal},
volume = {},
number = {},
pages = {},
doi = {10.1093/ismejo/wrae055},
pmid = {38552150},
issn = {1751-7370},
abstract = {Viruses impact microbial systems through killing hosts, horizontal gene transfer, and altering cellular metabolism, consequently impacting nutrient cycles. A virus-infected cell, a "virocell", is distinct from its uninfected sister cell as the virus commandeers cellular machinery to produce viruses rather than replicate cells. Problematically, virocell responses to the nutrient-limited conditions that abound in nature are poorly understood. Here we used a systems biology approach to investigate virocell metabolic reprogramming under nutrient limitation. Using transcriptomics, proteomics, lipidomics, and endo- and exo-metabolomics, we assessed how low phosphate (low-P) conditions impacted virocells of a marine Pseudoalteromonas host when independently infected by two unrelated phages (HP1 and HS2). With the combined stresses of infection and nutrient limitation, a set of nested responses were observed. First, low-P imposed common cellular responses on all cells (virocells and uninfected cells), including activating the canonical P-stress response, and decreasing transcription, translation, and extracellular organic matter consumption. Second, low-P imposed infection-specific responses (for both virocells), including enhancing nitrogen assimilation and fatty acid degradation, and decreasing extracellular lipid relative abundance. Third, low-P suggested virocell-specific strategies. Specifically, HS2-virocells regulated gene expression by increasing transcription and ribosomal protein production, whereas HP1-virocells accumulated host proteins, decreased extracellular peptide relative abundance, and invested in broader energy and resource acquisition. These results suggest that although environmental conditions shape metabolism in common ways regardless of infection, virocell-specific strategies exist to support viral replication during nutrient limitation, and a framework now exists for identifying metabolic strategies of nutrient-limited virocells in nature.},
}

@article {pmid38551849,
year = {2024},
author = {Masuda, T and Mareš, J and Shiozaki, T and Inomura, K and Fujiwara, A and Prášil, O},
title = {Crocosphaera watsonii - A widespread nitrogen-fixing unicellular marine cyanobacterium.},
journal = {Journal of phycology},
volume = {},
number = {},
pages = {},
doi = {10.1111/jpy.13450},
pmid = {38551849},
issn = {1529-8817},
support = {23-06593S//Grantová Agentura České Republiky/ ; JP23H02301//Japan Society for the Promotion of Science/ ; JPMJPR23GA//JST, PRESTO/ ; },
abstract = {Crocosphaera watsonii is a unicellular N2-fixing (diazotrophic) cyanobacterium observed in tropical and subtropical oligotrophic oceans. As a diazotroph, it can be a source of bioavailable nitrogen (N) to the microbial community in N-limited environments, and this may fuel primary production in the regions where it occurs. Crocosphaera watsonii has been the subject of intense study, both in culture and in field populations. Here, we summarize the current understanding of the phylogenetic and physiological diversity of C. watsonii, its distribution, and its ecological niche. Analysis of the relationships among the individual Crocosphaera species and related free-living and symbiotic lineages of diazotrophs based on the nifH gene have shown that the C. watsonii group holds a basal position and that its sequence is more similar to Rippkaea and Zehria than to other Crocosphaera species. This finding warrants further scrutiny to determine if the placement is related to a horizontal gene transfer event. Here, the nifH UCYN-B gene copy number from a recent synthesis effort was used as a proxy for relative C. watsonii abundance to examine patterns of C. watsonii distribution as a function of environmental factors, like iron and phosphorus concentration, and complimented with a synthesis of C. watsonii physiology. Furthermore, we have summarized the current knowledge of C. watsonii with regards to N2 fixation, photosynthesis, and quantitative modeling of physiology. Because N availability can limit primary production, C. watsonii is widely recognized for its importance to carbon and N cycling in ocean ecosystems, and we conclude this review by highlighting important topics for further research on this important species.},
}

@article {pmid38548766,
year = {2024},
author = {Pratt, CJ and Meili, CH and Jones, AL and Jackson, DK and England, EE and Wang, Y and Hartson, S and Rogers, J and Elshahed, MS and Youssef, NH},
title = {Anaerobic fungi in the tortoise alimentary tract illuminate early stages of host-fungal symbiosis and Neocallimastigomycota evolution.},
journal = {Nature communications},
volume = {15},
number = {1},
pages = {2714},
pmid = {38548766},
issn = {2041-1723},
support = {2029478//National Science Foundation (NSF)/ ; 2029478//National Science Foundation (NSF)/ ; },
abstract = {Anaerobic gut fungi (AGF, Neocallimastigomycota) reside in the alimentary tract of herbivores. While their presence in mammals is well documented, evidence for their occurrence in non-mammalian hosts is currently sparse. Culture-independent surveys of AGF in tortoises identified a unique community, with three novel deep-branching genera representing >90% of sequences in most samples. Representatives of all genera were successfully isolated under strict anaerobic conditions. Transcriptomics-enabled phylogenomic and molecular dating analyses indicated an ancient, deep-branching position in the AGF tree for these genera, with an evolutionary divergence time estimate of 104-112 million years ago (Mya). Such estimates push the establishment of animal-Neocallimastigomycota symbiosis from the late to the early Cretaceous. Further, tortoise-associated isolates (T-AGF) exhibited limited capacity for plant polysaccharides metabolism and lacked genes encoding several carbohydrate-active enzyme (CAZyme) families. Finally, we demonstrate that the observed curtailed degradation capacities and reduced CAZyme repertoire is driven by the paucity of horizontal gene transfer (HGT) in T-AGF genomes, compared to their mammalian counterparts. This reduced capacity was reflected in an altered cellulosomal production capacity in T-AGF. Our findings provide insights into the phylogenetic diversity, ecological distribution, evolutionary history, evolution of fungal-host nutritional symbiosis, and dynamics of genes acquisition in Neocallimastigomycota.},
}

@article {pmid38546735,
year = {2024},
author = {Klose, SM and Legione, AR and Bushell, RN and Browning, GF and Vaz, PK},
title = {Unveiling genome plasticity and a novel phage in Mycoplasma felis: Genomic investigations of four feline isolates.},
journal = {Microbial genomics},
volume = {10},
number = {3},
pages = {},
doi = {10.1099/mgen.0.001227},
pmid = {38546735},
issn = {2057-5858},
mesh = {Cats ; Animals ; Horses ; Australia ; Genomics ; *Mycoplasma/genetics ; *Felis ; *Bacteriophages ; },
abstract = {Mycoplasma felis has been isolated from diseased cats and horses, but to date only a single fully assembled genome of this species, of an isolate from a horse, has been characterized. This study aimed to characterize and compare the completely assembled genomes of four clinical isolates of M. felis from three domestic cats, assembled with the aid of short- and long-read sequencing methods. The completed genomes encoded a median of 759 ORFs (range 743-777) and had a median average nucleotide identity of 98.2 % with the genome of the available equid origin reference strain. Comparative genomic analysis revealed the occurrence of multiple horizontal gene transfer events and significant genome reassortment. This had resulted in the acquisition or loss of numerous genes within the Australian felid isolate genomes, encoding putative proteins involved in DNA transfer, metabolism, DNA replication, host cell interaction and restriction modification systems. Additionally, a novel mycoplasma phage was detected in one Australian felid M. felis isolate by genomic analysis and visualized using cryo-transmission electron microscopy. This study has highlighted the complex genomic dynamics in different host environments. Furthermore, the sequences obtained in this work will enable the development of new diagnostic tools, and identification of future infection control and treatment options for the respiratory disease complex in cats.},
}

Cats
Animals
Horses
Australia
Genomics
*Mycoplasma/genetics
*Felis
*Bacteriophages

@article {pmid38543613,
year = {2024},
author = {Mei, L and Song, Y and Liu, X and Li, K and Guo, X and Liu, L and Liu, Y and Kozlakidis, Z and Cheong, IH and Wang, D and Wei, Q},
title = {Characterization and Implications of IncP-2A Plasmid pMAS152 Harboring Multidrug Resistance Genes in Extensively Drug-Resistant Pseudomonas aeruginosa.},
journal = {Microorganisms},
volume = {12},
number = {3},
pages = {},
pmid = {38543613},
issn = {2076-2607},
support = {2022YFC2602200//National Key Research and Development Program of China/ ; Project No. National Pathogen Resource Center-NPRC-32//National Science and Technology Infrastructure of China/ ; },
abstract = {Bacterial antimicrobial resistance (AMR) poses a significant global public health challenge. The escalation of AMR is primarily attributed to the horizontal gene transfer (HGT) of antibiotic resistance genes (ARGs), often facilitated by plasmids. This underscores the critical need for a comprehensive understanding of the resistance mechanisms and transmission dynamics of these plasmids. In this study, we utilized in vitro drug sensitivity testing, conjugation transfer assays, and whole-genome sequencing to investigate the resistance mechanism of an extensively drug-resistant (XDR) Pseudomonas aeruginosa clinical isolate, MAS152. We specifically focused on analyzing the drug-resistant plasmid pMAS152 it harbors and its potential for widespread dissemination. Bioinformatics analysis revealed that MAS152 carries a distinct IncpP-2A plasmid, pMAS152, characterized by a 44.8 kb multidrug resistance (MDR) region. This region houses a 16S rRNA methyltransferase (16S-RMTase) gene, rmtB, conferring high-level resistance to aminoglycoside antibiotics. Notably, this region also contains an extended-spectrum β-Lactamase (ESBL) gene, blaPER-1, and an efflux pump operon, tmexCD-oprJ, which mediate resistance to β-Lactams and quinolone antibiotics, respectively. Such a combination of ARGs, unprecedented in reported plasmids, could significantly undermine the effectiveness of first-line antibiotics in treating P. aeruginosa infections. Investigation into the genetic environment of the MDR region suggests that Tn2 and IS91 elements may be instrumental in the horizontal transfer of rmtB. Additionally, a complex Class I integron with an ISCR1 structure, along with TnAs1, seems to facilitate the horizontal transfer of blaPER-1. The conjugation transfer assay, coupled with the annotation of conjugation-related genes and phylogenetic analysis, indicates that the plasmid pMAS152 functions as a conjugative plasmid, with other genus Pseudomonas species as potential hosts. Our findings provide vital insights into the resistance mechanisms and transmission potential of the XDR P. aeruginosa isolate MAS152, underlining the urgent need for novel strategies to combat the spread of AMR. This study highlights the complex interplay of genetic elements contributing to antibiotic resistance and underscores the importance of continuous surveillance of emerging ARGs in clinical isolates.},
}

@article {pmid38543545,
year = {2024},
author = {Skwor, T and Jones, DC and Cahak, C and Newton, RJ},
title = {First Report and Characterization of a Plasmid-Encoded blaSFO-1 in a Multi-Drug-Resistant Aeromonas hydrophila Clinical Isolate.},
journal = {Microorganisms},
volume = {12},
number = {3},
pages = {},
pmid = {38543545},
issn = {2076-2607},
abstract = {Antibiotic resistance remains one of the most pressing public health issues facing the world today. At the forefront of this battle lies the ever-increasing identification of extended-spectrum beta-lactamases and carbapenemases within human pathogens, conferring resistance towards broad-spectrum and last-resort antimicrobials. This study was prompted due to the identification of a pathogenic Aeromonas hydrophila isolate (strain MAH-4) collected from abdominal fluid, which presented a robust resistance pattern against second-, third-, and fourth-generation cephalosporins, ertapenem, ciprofloxacin, gentamicin, levofloxacin and moxifloxacin, and beta lactam/beta-lactamase inhibitor combinations. Whole genome sequencing was performed and identified a 328 kb plasmid (pMAH4) encoding 10 antibiotic resistance genes, including blaSFO-1, blaTEM-1, and blaOXA-1 of A. hydrophia MAH-4. This is the first report of beta-lactamase SFO-1 within a clinical strain of Aeromonas. Due to the remarkable sequence identity of pMAH4 to plasmids associated with Enterobacterales genera like Klebsiella and the extensive capabilities of Aeromonas for horizontal gene transfer, our identification of a clinical isolate encoding SFO-1 on a plasmid suggests antibiotic resistance gene mobility between Enterobacterales and non-Enterobacterales species.},
}

@article {pmid38542054,
year = {2024},
author = {Barathan, M and Ng, SL and Lokanathan, Y and Ng, MH and Law, JX},
title = {Unseen Weapons: Bacterial Extracellular Vesicles and the Spread of Antibiotic Resistance in Aquatic Environments.},
journal = {International journal of molecular sciences},
volume = {25},
number = {6},
pages = {},
doi = {10.3390/ijms25063080},
pmid = {38542054},
issn = {1422-0067},
support = {DIP-2023-011//National University of Malaysia/ ; FF-2021-518//Faculty of Medicine, Universiti Kebangsaan Malaysia/ ; },
abstract = {This paper sheds light on the alarming issue of antibiotic resistance (ABR) in aquatic environments, exploring its detrimental effects on ecosystems and public health. It examines the multifaceted role of antibiotic use in aquaculture, agricultural runoff, and industrial waste in fostering the development and dissemination of resistant bacteria. The intricate interplay between various environmental factors, horizontal gene transfer, and bacterial extracellular vesicles (BEVs) in accelerating the spread of ABR is comprehensively discussed. Various BEVs carrying resistance genes like blaCTX-M, tetA, floR, and sul/I, as well as their contribution to the dominance of multidrug-resistant bacteria, are highlighted. The potential of BEVs as both a threat and a tool in combating ABR is explored, with promising strategies like targeted antimicrobial delivery systems and probiotic-derived EVs holding significant promise. This paper underscores the urgency of understanding the intricate interplay between BEVs and ABR in aquatic environments. By unraveling these unseen weapons, we pave the way for developing effective strategies to mitigate the spread of ABR, advocating for a multidisciplinary approach that includes stringent regulations, enhanced wastewater treatment, and the adoption of sustainable practices in aquaculture.},
}

@article {pmid38539090,
year = {2024},
author = {Kumar, G and Balakrishna, K and Mukhopadhyay, C and Kalwaje Eshwara, V},
title = {Comparison of integron mediated antimicrobial resistance in clinical isolates of Escherichia coli from urinary and bacteremic sources.},
journal = {BMC microbiology},
volume = {24},
number = {1},
pages = {102},
pmid = {38539090},
issn = {1471-2180},
abstract = {BACKGROUND: Antimicrobial resistance (AMR) is a global threat driven mainly by horizontal gene transfer (HGT) mechanisms through mobile genetic elements (MGEs) including integrons. The variable region (VR) of an integron can acquire or excise gene cassettes (GCs) that confer resistance to antibiotics based on the selection pressure. Escherichia coli plays a significant role in the genetic transfer of resistance determinants to other Gram-negative bacteria. Current study is aimed to detect and compare integron-mediated resistance in clinical isolates of E. coli. Unique isolates of E. coli from urine or blood cultures were studied for their antimicrobial resistance patterns and integrons were detected using polymerase chain reaction assays followed by Sanger sequencing of GCs.

RESULTS: During the study period, a total of 470 E. coli isolates were obtained, 361 (76.8%) from urinary and 109 (23.1%) from bacteremic sources. Class 1 integrons were detected in 66 (18.2%) and 26 (23.8%) isolates respectively. Urinary isolates of E. coli harbouring Class 1 integrons demonstrated significantly higher rates of resistance (p < 0.05) for most antibiotics (12/16, 75%) compared to integron negative isolates. Although not statistically significant, similar differences were observed in bacteremic isolates. Among the urinary isolates, 27 (40.9%) had a VR, in which the most common GC array detected was DfrA17-AadA5 (n = 14), followed by DfrA5 (n = 4) and DfrA12 (n = 3). Among bacteremic isolates, only 4 (15.3%) had a VR, all of which were carrying DfrA17. The detected GC array correlated with the respective isolates' phenotypic resistance patterns.

CONCLUSION: We found a strong correlation between integron positivity and trimethoprim resistance among E. coli from urinary sources. Although higher rates of resistance were observed in bacteremic isolates, they mostly carried empty integrons.},
}

@article {pmid38538528,
year = {2024},
author = {Chiquito-Contreras, CJ and Meza-Menchaca, T and Guzmán-López, O and Vásquez, EC and Ricaño-Rodríguez, J},
title = {Molecular Insights into Plant-Microbe Interactions: A Comprehensive Review of Key Mechanisms.},
journal = {Frontiers in bioscience (Elite edition)},
volume = {16},
number = {1},
pages = {9},
doi = {10.31083/j.fbe1601009},
pmid = {38538528},
issn = {1945-0508},
abstract = {In most ecosystems, plants establish complex symbiotic relationships with organisms, such as bacteria and fungi, which significantly influence their health by promoting or inhibiting growth. These relationships involve biochemical exchanges at the cellular level that affect plant physiology and have evolutionary implications, such as species diversification, horizontal gene transfer, symbiosis and mutualism, environmental adaptation, and positive impacts on community structure and biodiversity. For these reasons, contemporary research, moving beyond observational studies, seeks to elucidate the molecular basis of these interactions; however, gaps in knowledge remain. This is particularly noticeable in understanding how plants distinguish between beneficial and antagonistic microorganisms. In light of the above, this literature review aims to address some of these gaps by exploring the key mechanisms in common interspecies relationships. Thus, our study presents novel insights into these evolutionary archetypes, focusing on the antibiosis process and microbial signaling, including chemotaxis and quorum sensing. Additionally, it examined the biochemical basis of endophytism, pre-mRNA splicing, and transcriptional plasticity, highlighting the roles of transcription factors and epigenetic regulation in the functions of the interacting organisms. These findings emphasize the importance of understanding these confluences in natural environments, which are crucial for future theoretical and practical applications, such as improving plant nutrition, protecting against pathogens, developing transgenic crops, sustainable agriculture, and researching disease mechanisms. It was concluded that because of the characteristics of the various biomolecules involved in these biological interactions, there are interconnected molecular networks in nature that give rise to different ecological scaffolds. These networks integrate a myriad of functionally organic units that belong to various kingdoms. This interweaving underscores the complexity and multidisciplinary integration required to understand plant-microbe interactions at the molecular level. Regarding the limitations inherent in this study, it is recognized that researchers face significant obstacles. These include technical difficulties in experimentation and fieldwork, as well as the arduous task of consolidating and summarizing findings for academic articles. Challenges range from understanding complex ecological and molecular dynamics to unbiased and objective interpretation of diverse and ever-changing literature.},
}

@article {pmid38536216,
year = {2024},
author = {Dechêne-Tempier, M and de Boisséson, C and Lucas, P and Bougeard, S and Libante, V and Marois-Créhan, C and Payot, S},
title = {Virulence genes, resistome and mobilome of Streptococcus suis strains isolated in France.},
journal = {Microbial genomics},
volume = {10},
number = {3},
pages = {},
doi = {10.1099/mgen.0.001224},
pmid = {38536216},
issn = {2057-5858},
mesh = {Humans ; Animals ; Swine ; *Streptococcus suis ; Virulence ; France ; Virulence Factors ; DNA ; },
abstract = {Streptococcus suis is a leading cause of infection in pigs, causing extensive economic losses. In addition, it can also infect wild fauna, and can be responsible for severe infections in humans. Increasing antimicrobial resistance (AMR) has been described in S. suis worldwide and most of the AMR genes are carried by mobile genetic elements (MGEs). This contributes to their dissemination by horizontal gene transfer. A collection of 102 strains isolated from humans, pigs and wild boars in France was subjected to whole genome sequencing in order to: (i) study their genetic diversity, (ii) evaluate their content in virulence-associated genes, (iii) decipher the mechanisms responsible for their AMR and their association with MGEs, and (iv) study their ability to acquire extracellular DNA by natural transformation. Analysis by hierarchical clustering on principal components identified a few virulence-associated factors that distinguish invasive CC1 strains from the other strains. A plethora of AMR genes (n=217) was found in the genomes. Apart from the frequently reported erm(B) and tet(O) genes, more recently described AMR genes were identified [vga(F)/sprA, vat(D)]. Modifications in PBPs/MraY and GyrA/ParC were detected in the penicillin- and fluoroquinolone-resistant isolates respectively. New AMR gene-MGE associations were detected. The majority of the strains have the full set of genes required for competence, i.e for the acquisition of extracellular DNA (that could carry AMR genes) by natural transformation. Hence the risk of dissemination of these AMR genes should not be neglected.},
}

Humans
Animals
Swine
*Streptococcus suis
Virulence
France
Virulence Factors
DNA

@article {pmid38534711,
year = {2024},
author = {Li, Q and Li, J and He, T and Ji, X and Wei, R and Yu, M and Wang, R},
title = {Sub-MIC Antibiotics Modulate Productions of Outer Membrane Vesicles in Tigecycline-Resistant Escherichia coli.},
journal = {Antibiotics (Basel, Switzerland)},
volume = {13},
number = {3},
pages = {},
pmid = {38534711},
issn = {2079-6382},
support = {32102728//National Natural Science Foundation of China/ ; ZX(21)1224//Exploration and Disruptive Innovation Projects of Jiangsu Academy of Agricultural Sciences/ ; GJFP20230305//National Agricultural Product Quality and Safety Risk Assessment/ ; },
abstract = {Antimicrobial resistance (AMR) has been recognized as one of the most important crises affecting global human health in the 21st century. Tigecycline is one of the last resort antibiotics for treating severe infections caused by multi-drug resistant Enterobacteriaceae. However, the mobile resistance gene tet(X4), which could mediate high-level tigecycline resistance, was discovered in 2019. The outer membrane vesicle (OMV) has been recognized as a new route for horizontal gene transfer; antimicrobial resistant bacteria also have the ability to secret OMVs, while little is known about the impact of antibiotics on the secretion and characteristics of OMVs from tigecycline resistant bacteria till now. This study aimed to investigate the effects of antibiotics on the production and traits of a tigecycline resistant Escherichia coli strain of 47EC. The results showed that sub-inhibitory (1/2 MIC or 1/4 MIC) concentrations of gentamicin, meropenem, ceftazidime, chloramphenicol, tigecycline, ciprofloxacin, polymycin, rifaximin and mitomycin C could significantly increase the secretion of OMVs (0.713 ± 0.05~6.333 ± 0.15 mg/mL) from E. coli 47EC compared to the respective untreated control (0.709 ± 0.03 mg/mL). In addition, the particle sizes of OMVs were generally larger, and the zeta potential were lower in the antibiotics-treated groups than those of the antibiotic-free group. The copy numbers of the tigecycline resistance gene of tet(X4) in the OMVs of most antimicrobial-treated groups were higher than that of the control group. Moreover, transcriptome analysis on ciprofloxacin-treated E. coli 47EC indicated that the SOS response and prophage activation might participate in the ciprofloxacin-induced OMV formation. In conclusion, the clinical application of antibiotics in treating bacterial infections, especially multi-drug resistant bacteria, might lead to the increased secretion of bacterial OMVs and the enrichment of antimicrobial-resistant genes in the OMVs.},
}

@article {pmid38534448,
year = {2024},
author = {Duwor, S and Brites, D and Mäser, P},
title = {Phylogenetic Analysis of Pyruvate-Ferredoxin Oxidoreductase, a Redox Enzyme Involved in the Pharmacological Activation of Nitro-Based Prodrugs in Bacteria and Protozoa.},
journal = {Biology},
volume = {13},
number = {3},
pages = {},
doi = {10.3390/biology13030178},
pmid = {38534448},
issn = {2079-7737},
abstract = {The present frontrunners in the chemotherapy of infections caused by protozoa are nitro-based prodrugs that are selectively activated by PFOR-mediated redox reactions. This study seeks to analyze the distribution of PFOR in selected protozoa and bacteria by applying comparative genomics to test the hypothesis that PFOR in eukaryotes was acquired through horizontal gene transfer (HGT) from bacteria. Furthermore, to identify other putatively acquired genes, proteome-wide and gene enrichment analyses were used. A plausible explanation for the patchy occurrence of PFOR in protozoa is based on the hypothesis that bacteria are potential sources of genes that enhance the adaptation of protozoa in hostile environments. Comparative genomics of Entamoeba histolytica and the putative gene donor, Desulfovibrio vulgaris, identified eleven candidate genes for HGT involved in intermediary metabolism. If these results can be reproduced in other PFOR-possessing protozoa, it would provide more validated evidence to support the horizontal transfer of pfor from bacteria.},
}

@article {pmid38533399,
year = {2024},
author = {Peng, D and Wang, Z and Tian, J and Wang, W and Guo, S and Dai, X and Yin, H and Li, L},
title = {Phyllosphere bacterial community dynamics in response to bacterial wildfire disease: succession and interaction patterns.},
journal = {Frontiers in plant science},
volume = {15},
number = {},
pages = {1331443},
pmid = {38533399},
issn = {1664-462X},
abstract = {Plants interact with complex microbial communities in which microorganisms play different roles in plant development and health. While certain microorganisms may cause disease, others promote nutrient uptake and resistance to stresses through a variety of mechanisms. Developing plant protection measures requires a deeper comprehension of the factors that influence multitrophic interactions and the organization of phyllospheric communities. High-throughput sequencing was used in this work to investigate the effects of climate variables and bacterial wildfire disease on the bacterial community's composition and assembly in the phyllosphere of tobacco (Nicotiana tabacum L.). The samples from June (M1), July (M2), August (M3), and September (M4) formed statistically separate clusters. The assembly of the whole bacterial population was mostly influenced by stochastic processes. PICRUSt2 predictions revealed genes enriched in the M3, a period when the plant wildfire disease index reached climax, were associated with the development of the wildfire disease (secretion of virulence factor), the enhanced metabolic capacity and environmental adaption. The M3 and M4 microbial communities have more intricate molecular ecological networks (MENs), bursting with interconnections within a densely networked bacterial population. The relative abundances of plant-beneficial and antagonistic microbes Clostridiales, Bacillales, Lactobacillales, and Sphingobacteriales, showed significant decrease in severally diseased sample (M3) compared to the pre-diseased samples (M1/M2). Following the results of MENs, we further test if the correlating bacterial pairs within the MEN have the possibility to share functional genes and we have unraveled 139 entries of such horizontal gene transfer (HGT) events, highlighting the significance of HGT in shaping the adaptive traits of plant-associated bacteria across the MENs, particularly in relation to host colonization and pathogenicity.},
}

@article {pmid38530969,
year = {2024},
author = {Nasser, F and Gaudreau, A and Lubega, S and Zaker, A and Xia, X and Mer, AS and D'Costa, VM},
title = {Characterization of the diversity of type IV secretion system-encoding plasmids in Acinetobacter.},
journal = {Emerging microbes & infections},
volume = {13},
number = {1},
pages = {2320929},
doi = {10.1080/22221751.2024.2320929},
pmid = {38530969},
issn = {2222-1751},
abstract = {The multi-drug resistant pathogen Acinetobacter baumannii has gained global attention as an important clinical challenge. Owing to its ability to survive on surfaces, its capacity for horizontal gene transfer, and its resistance to front-line antibiotics, A. baumannii has established itself as a successful pathogen. Bacterial conjugation is a central mechanism for pathogen evolution. The epidemic multidrug-resistant A. baumannii ACICU harbours a plasmid encoding a Type IV Secretion System (T4SS) with homology to the E. coli F-plasmid, and plasmids with homologous gene clusters have been identified in several A. baumannii sequence types. However the genetic and host strain diversity, global distribution, and functional ability of this group of plasmids is not fully understood. Using systematic analysis, we show that pACICU2 belongs to a group of almost 120 T4SS-encoding plasmids within four different species of Acinetobacter and one strain of Klebsiella pneumoniae from human and environmental origin, and globally distributed across 20 countries spanning 4 continents. Genetic diversity was observed both outside and within the T4SS-encoding cluster, and 47% of plasmids harboured resistance determinants, with two plasmids harbouring eleven. Conjugation studies with an extensively drug-resistant (XDR) strain showed that the XDR plasmid could be successfully transferred to a more divergent A. baumanii, and transconjugants exhibited the resistance phenotype of the plasmid. Collectively, this demonstrates that these T4SS-encoding plasmids are globally distributed and more widespread among Acinetobacter than previously thought, and that they represent an important potential reservoir for future clinical concern.},
}

@article {pmid38529905,
year = {2024},
author = {Crowley, C and Selvaraj, A and Hariharan, A and Healy, CM and Moran, GP},
title = {Fusobacterium nucleatum subsp. polymorphum recovered from malignant and potentially malignant oral disease exhibit heterogeneity in adhesion phenotypes and adhesin gene copy number, shaped by inter-subspecies horizontal gene transfer and recombination-derived mosaicism.},
journal = {Microbial genomics},
volume = {10},
number = {3},
pages = {},
doi = {10.1099/mgen.0.001217},
pmid = {38529905},
issn = {2057-5858},
mesh = {Humans ; *Mosaicism ; Phylogeny ; *Gene Transfer, Horizontal ; Fusobacterium/genetics ; Phenotype ; Gene Dosage ; },
abstract = {Fusobacterium nucleatum is an anaerobic commensal of the oral cavity associated with periodontitis and extra-oral diseases, including colorectal cancer. Previous studies have shown an increased relative abundance of this bacterium associated with oral dysplasia or within oral tumours. Using direct culture, we found that 75 % of Fusobacterium species isolated from malignant or potentially malignant oral mucosa were F. nucleatum subsp. polymorphum. Whole genome sequencing and pangenome analysis with Panaroo was carried out on 76 F. nucleatum subsp. polymorphum genomes. F. nucleatum subsp. polymorphum was shown to possesses a relatively small core genome of 1604 genes in a pangenome of 7363 genes. Phylogenetic analysis based on the core genome shows the isolates can be separated into three main clades with no obvious genotypic associations with disease. Isolates recovered from healthy and diseased sites in the same patient are generally highly related. A large repertoire of adhesins belonging to the type V secretion system (TVSS) could be identified with major variation in repertoire and copy number between strains. Analysis of intergenic recombination using fastGEAR showed that adhesin complement is shaped by horizontal gene transfer and recombination. Recombination events at TVSS adhesin genes were not only common between lineages of subspecies polymorphum, but also between different subspecies of F. nucleatum. Strains of subspecies polymorphum with low copy numbers of TVSS adhesin encoding genes tended to have the weakest adhesion to oral keratinocytes. This study highlights the genetic heterogeneity of F. nucleatum subsp. polymorphum and provides a new framework for defining virulence in this organism.},
}

Humans
*Mosaicism
Phylogeny
*Gene Transfer, Horizontal
Fusobacterium/genetics
Phenotype
Gene Dosage

@article {pmid38527381,
year = {2024},
author = {Ferilli, F and Lione, G and Gonthier, P and Turina, M and Forgia, M},
title = {First detection of mycoviruses in Gnomoniopsis castaneae suggests a putative horizontal gene transfer event between negative-sense and double-strand RNA viruses.},
journal = {Virology},
volume = {594},
number = {},
pages = {110057},
doi = {10.1016/j.virol.2024.110057},
pmid = {38527381},
issn = {1096-0341},
abstract = {Gnomoniopsis castaneae is an ascomycetous fungus mainly known as a major pathogen of chestnut causing nut rots, although it is often found as an endophyte in chestnut tissues. To date, no virus has been reported as associated with to this fungus. Here, a collection of G. castaneae isolates from several European countries was screened to detect mycoviruses infecting the fungus: for the first time we report the identification and prevalence of mitovirus Gnomoniopsis castaneae mitovirus 1 (GcMV1) and the chrysovirus Gnomoniopsis castaneae chrysovirus 1 (GcCV1). Interestingly, we provide evidence supporting a putative horizontal gene transfer between members of the phyla Negarnaviricota and Duplornaviricota: a small putative protein of unknown function encoded on the RNA3 of GcCV1 (Chrysoviridae) has homologs in the genome of viruses of the family Mymonaviridae.},
}

@article {pmid38521802,
year = {2024},
author = {Asad, A and Jahan, I and Munni, MA and Begum, R and Mukta, MA and Saif, K and Faruque, SN and Hayat, S and Islam, Z},
title = {Multidrug-resistant conjugative plasmid carrying mphA confers increased antimicrobial resistance in Shigella.},
journal = {Scientific reports},
volume = {14},
number = {1},
pages = {6947},
pmid = {38521802},
issn = {2045-2322},
support = {NIH FIC TW010540/TW/FIC NIH HHS/United States ; K43TW011447/TW/FIC NIH HHS/United States ; },
mesh = {Child ; Humans ; Anti-Bacterial Agents/pharmacology/therapeutic use ; *Dysentery, Bacillary/drug therapy/epidemiology ; Macrolides/pharmacology/therapeutic use ; Drug Resistance, Bacterial/genetics ; *Shigella ; Azithromycin/pharmacology/therapeutic use ; Ciprofloxacin/pharmacology/therapeutic use ; Ceftriaxone/pharmacology ; Microbial Sensitivity Tests ; Protein Synthesis Inhibitors/pharmacology ; Plasmids/genetics ; },
abstract = {Shigellosis remains a common gastrointestinal disease mostly in children < 5 years of age in developing countries. Azithromycin (AZM), a macrolide, is currently the first-line treatment for shigellosis in Bangladesh; ciprofloxacin (CIP) and ceftriaxone (CRO) are also used frequently. We aimed to evaluate the current epidemiology of antimicrobial resistance (AMR) and mechanism(s) of increasing macrolide resistance in Shigella in Bangladesh. A total of 2407 clinical isolates of Shigella from 2009 to 2016 were studied. Over the study period, Shigella sonnei was gradually increasing and become predominant (55%) over Shigella flexneri (36%) by 2016. We used CLSI-guided epidemiological cut-off value (ECV) for AZM in Shigella to set resistance breakpoints (zone-diameter ≤ 15 mm for S. flexneri and ≤ 11 mm for S. sonnei). Between 2009 and 2016, AZM resistance increased from 22% to approximately 60%, CIP resistance increased by 40%, and CRO resistance increased from zero to 15%. The mphA gene was the key macrolide resistance factor in Shigella; a 63MDa conjugative middle-range plasmid was harboring AZM and CRO resistance factors. Our findings show that, especially after 2014, there has been a rapid increase in resistance to the three most effective antibiotics. The rapid spread of macrolide (AZM) resistance genes among Shigella are driven by horizontal gene transfer rather than direct lineage.},
}

Child
Humans
Anti-Bacterial Agents/pharmacology/therapeutic use
*Dysentery, Bacillary/drug therapy/epidemiology
Macrolides/pharmacology/therapeutic use
Drug Resistance, Bacterial/genetics
*Shigella
Azithromycin/pharmacology/therapeutic use
Ciprofloxacin/pharmacology/therapeutic use
Ceftriaxone/pharmacology
Microbial Sensitivity Tests
Protein Synthesis Inhibitors/pharmacology
Plasmids/genetics