Biochemistry, Genetics and Molecular Biology › Endocrinology

Vibrio bacteria research studies

Works Count: 52893

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Description

This cluster of papers explores the dynamics, pathogenesis, and epidemiology of cholera bacteria, primarily focusing on Vibrio cholerae. It covers topics such as the Type VI Secretion System, viable but non-culturable state, climate influence on disease spread, bacterial transmission, environmental reservoirs, and the global impact of cholera.

Keywords

Cholera; Vibrio cholerae; Type VI Secretion System; Bacterial Pathogenesis; Epidemiology; Viable but Non-culturable State; Climate Influence; Bacterial Transmission; Environmental Reservoirs; Global Impact

Manual for the identification of medical bacteria.

1965-01-01

S. T. Cowan , Karl Steel

Manual for the identification of medical bacteria , Manual for the identification of medical bacteria , مرکز فناوری اطلاعات و اطلاع رسانی کشاورزی Manual for the identification of medical bacteria , Manual for the identification of medical bacteria , مرکز فناوری اطلاعات و اطلاع رسانی کشاورزی

A novel suicide vector and its use in construction of insertion mutations: osmoregulation of outer membrane proteins and virulence determinants in Vibrio cholerae requires toxR

1988-06-01

Virginia L. Miller , John J. Mekalanos

The toxR gene of Vibrio cholerae encodes a transmembrane, DNA-binding protein that activates transcription of the cholera toxin operon and a gene (tcpA) for the major subunit of a pilus … The toxR gene of Vibrio cholerae encodes a transmembrane, DNA-binding protein that activates transcription of the cholera toxin operon and a gene (tcpA) for the major subunit of a pilus colonization factor. We constructed site-directed insertion mutations in the toxR gene by a novel method employing the chromosomal integration of a mobilizable suicide plasmid containing a portion of the toxR coding sequence. Mutants containing these new toxR alleles had an altered outer membrane protein profile, suggesting that two major outer membrane proteins (OmpT and OmpU) might be under the control of toxR. Physiological studies indicated that varying the concentration of the amino acids asparagine, arginine, glutamate, and serine caused coordinate changes in the expression of cholera toxin, TcpA, OmpT, and OmpU. Changes in the osmolarity of a tryptone-based medium also produced coordinate changes in the expression of these proteins. Other environmental signals (temperature and pH) had a more pronounced effect on the expression of cholera toxin and TcpA than they did on the outer membrane proteins. These results suggest that certain environmental signals (i.e., osmolarity and the presence of amino acids) are tightly coupled to the expression of toxR-regulated proteins and therefore may be signals that are directly sensed by the ToxR protein.

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Roles of Pseudomonas aeruginosa las and rhl quorum-sensing systems in control of elastase and rhamnolipid biosynthesis genes

1997-09-01

James P. Pearson , Everett C. Pesci , Barbara H. Iglewski

Two quorum-sensing systems (las and rhl) regulate virulence gene expression in Pseudomonas aeruginosa. The las system consists of a transcriptional activator, LasR, and LasI, which directs the synthesis of the … Two quorum-sensing systems (las and rhl) regulate virulence gene expression in Pseudomonas aeruginosa. The las system consists of a transcriptional activator, LasR, and LasI, which directs the synthesis of the autoinducer N-(3-oxododecanoyl) homoserine lactone (PAI-1). Induction of lasB (encoding elastase) and other virulence genes requires LasR and PAI-1. The rhl system consists of a putative transcriptional activator, RhlR, and RhlI, which directs the synthesis of N-butyryl homoserine lactone (PAI-2). Rhamnolipid production in P. aeruginosa has been reported to require both the rhl system and rhlAB (encoding a rhamnosyltransferase). Here we report the generation of a delta lasI mutant and both delta lasI delta rhlI and delta lasR rhlR::Tn501 double mutants of strain PAO1. Rhamnolipid production and elastolysis were reduced in the delta lasI single mutant and abolished in the double-mutant strains. rhlAB mRNA was not detected in these strains at mid-logarithmic phase but was abundant in the parental strain. Further RNA analysis of the wild-type strain revealed that rhlAB is organized as an operon. The rhlAB transcriptional start was mapped, and putative sigma 54 and sigma 70 promoters were identified upstream. To define components required for rhlAB expression, we developed a bioassay in Escherichia coli and demonstrated that PAI-2 and RhlR are required and sufficient for expression of rhlA. To characterize the putative interaction between PAI-2 and RhlR, we demonstrated that [3H]PAI-2 binds to E. coli cells expressing RhlR and not to those expressing LasR. Finally, the specificity of the las and rhl systems was examined in E. coli bioassays. The las system was capable of mildly activating rhlA, and similarly, the rhl system partly activated lasB. However; these effects were much less than the activation of rhlA by the rhl system and lasB by the las system. The results presented here further characterize the roles of the rhl and las quorum-sensing systems in virulence gene expression.

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Quorum sensing controls biofilm formation in Vibrio cholerae

2003-08-20

Brian K. Hammer , Bonnie L. Bassler

Summary Multiple quorum‐sensing circuits function in parallel to control virulence and biofilm formation in Vibrio cholerae . In contrast to other bacterial pathogens that induce virulence factor production and/or biofilm … Summary Multiple quorum‐sensing circuits function in parallel to control virulence and biofilm formation in Vibrio cholerae . In contrast to other bacterial pathogens that induce virulence factor production and/or biofilm formation at high cell density in the presence of quorum‐sensing autoinducers, V. cholerae represses these behaviours at high cell density. Consistent with this, we show here that V. cholerae strains ‘locked’ in the regulatory state mimicking low cell density are enhanced for biofilm production whereas mutants ‘locked’ in the regulatory state mimicking high cell density are incapable of producing biofilms. The quorum‐sensing cascade we have identified in V. cholerae regulates the transcription of genes involved in exopolysaccharide production (EPS), and variants that produce EPS and form biofilms arise at high frequency from non‐EPS, non‐biofilm producing strains. Our data show that spontaneous mutation of the transcriptional regulator hapR is responsible for this effect. Several toxigenic strains of V. cholerae possess a naturally occurring frameshift mutation in hapR . Thus, the distinct environments occupied by this aquatic pathogen presumably include niches where cell‐cell communication is crucial, as well as ones where loss of quorum sensing via hapR mutation confers a selective advantage. Bacterial biofilms could represent a complex habitat where such differentiation occurs.

[31] Analysis and construction of stable phenotypes in gram-negative bacteria with Tn5- and Tn10-derived minitransposons

1994-01-01

Vı́ctor de Lorenzo , Kenneth N. Timmis

Environmental signals controlling expression of virulence determinants in bacteria

1992-01-01

John J. Mekalanos

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A two-component regulatory system (phoP phoQ) controls Salmonella typhimurium virulence.

1989-07-01

Samuel I. Miller , A M Kukral , John J. Mekalanos

We have determined that Salmonella typhimurium strains with mutations in the positive regulatory locus phoP are markedly attenuated in virulence for BALB/c mice. The DNA sequence for the phoP locus … We have determined that Salmonella typhimurium strains with mutations in the positive regulatory locus phoP are markedly attenuated in virulence for BALB/c mice. The DNA sequence for the phoP locus indicates that it is composed of two genes present in an operon, termed phoP and phoQ. The deduced amino acid sequence of the phoP and phoQ gene products are highly similar to other members of bacterial two-component transcriptional regulators that respond to environmental stimuli. S. typhimurium strains with transposon insertions that create transcriptional and translational gene fusions that require phoP and phoQ for expression have been isolated and have different chromosomal locations, indicating that this system is a regulon. One of these fusion strains, containing a mutation in a gene termed pagC, has a virulence defect. Other strains, including those containing mutations in the phoN gene, encoding an acid phosphatase, have wild-type virulence. Strains with pagC, phoP, or phoQ mutations have decreased survival in cultured mouse macrophages. When used as live vaccines in mice, strains with phoP or phoQ mutations afford partial protection to subsequent challenge by wild-type S. typhimurium.

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Identification of a conserved bacterial protein secretion system in Vibrio cholerae using the Dictyostelium host model system

2006-01-23

Stefan Pukatzki , Amy T. , Derek Sturtevant +5 more

The bacterium Vibrio cholerae, like other human pathogens that reside in environmental reservoirs, survives predation by unicellular eukaryotes. Strains of the O1 and O139 serogroups cause cholera, whereas non-O1/non-O139 strains … The bacterium Vibrio cholerae, like other human pathogens that reside in environmental reservoirs, survives predation by unicellular eukaryotes. Strains of the O1 and O139 serogroups cause cholera, whereas non-O1/non-O139 strains cause human infections through poorly defined mechanisms. Using Dictyostelium discoideum as a model host, we have identified a virulence mechanism in a non-O1/non-O139 V. cholerae strain that involves extracellular translocation of proteins that lack N-terminal hydrophobic leader sequences. Accordingly, we have named these genes "VAS" genes for virulence-associated secretion, and we propose that these genes encode a prototypic "type VI" secretion system. We show that vas genes are required for cytotoxicity of V. cholerae cells toward Dictyostelium amoebae and mammalian J774 macrophages by a contact-dependent mechanism. A large number of Gram-negative bacterial pathogens carry genes homologous to vas genes and potential effector proteins secreted by this pathway (i.e., hemolysin-coregulated protein and VgrG). Mutations in vas homologs in other bacterial species have been reported to attenuate virulence in animals and cultured macrophages. Thus, the genes encoding the VAS-related, type VI secretion system likely play an important conserved function in microbial pathogenesis and represent an additional class of targets for vaccine and antimicrobial drug-based therapies.

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Comparison of propidium monoazide with ethidium monoazide for differentiation of live vs. dead bacteria by selective removal of DNA from dead cells

2006-06-07

Andreas Nocker , Ching-Ying Cheung , Anne K. Camper

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Lysogenic Conversion by a Filamentous Phage Encoding Cholera Toxin

1996-06-28

Matthew K. Waldor , John J. Mekalanos

Vibrio cholerae , the causative agent of cholera, requires two coordinately regulated factors for full virulence: cholera toxin (CT), a potent enterotoxin, and toxin-coregulated pili (TCP), surface organelles required for … Vibrio cholerae , the causative agent of cholera, requires two coordinately regulated factors for full virulence: cholera toxin (CT), a potent enterotoxin, and toxin-coregulated pili (TCP), surface organelles required for intestinal colonization. The structural genes for CT are shown here to be encoded by a filamentous bacteriophage (designated CTXφ), which is related to coliphage M13. The CTXφ genome chromosomally integrated or replicated as a plasmid. CTXφ used TCP as its receptor and infected V. cholerae cells within the gastrointestinal tracts of mice more efficiently than under laboratory conditions. Thus, the emergence of toxigenic V. cholerae involves horizontal gene transfer that may depend on in vivo gene expression.

Viable but Non-Culturable Vibrio cholerae and Related Pathogens in the Environment: Implications for Release of Genetically Engineered Microorganisms

1985-09-01

Rita R. Colwell , P R Brayton , D. Jay Grimes +3 more

The importance of the viable but non-culturable state in human bacterial pathogens

2014-06-02

Laam Li , Nilmini Mendis , Hana Trigui +2 more

Many bacterial species have been found to exist in a viable but non-culturable (VBNC) state since its discovery in 1982. VBNC cells are characterized by a loss of culturability on … Many bacterial species have been found to exist in a viable but non-culturable (VBNC) state since its discovery in 1982. VBNC cells are characterized by a loss of culturability on routine agar, which impairs their detection by conventional plate count techniques. This leads to an underestimation of total viable cells in environmental or clinical samples, and thus poses a risk to public health. In this review, we present recent findings on the VBNC state of human bacterial pathogens. The characteristics of VBNC cells, including the similarities and differences to viable, culturable cells and dead cells, and different detection methods are discussed. Exposure to various stresses can induce the VBNC state, and VBNC cells may be resuscitated back to culturable cells under suitable stimuli. The conditions that trigger the induction of the VBNC state and resuscitation from it are summarized and the mechanisms underlying these two processes are discussed. Last but not least, the significance of VBNC cells and their potential influence on human health are also reviewed.

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The Small RNA Chaperone Hfq and Multiple Small RNAs Control Quorum Sensing in Vibrio harveyi and Vibrio cholerae

2004-07-01

Derrick H. Lenz , Kenny C. Mok , Brendan N. Lilley +3 more

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Use of phoA gene fusions to identify a pilus colonization factor coordinately regulated with cholera toxin.

1987-05-01

Robert K. Taylor , Virginia L. Miller , D Furlong +1 more

The transposon TnphoA was used to generate fusions between phoA, the gene for alkaline phosphatase (PhoA), and genes encoding proteins that are secreted by Vibrio cholerae. One of the PhoA+ … The transposon TnphoA was used to generate fusions between phoA, the gene for alkaline phosphatase (PhoA), and genes encoding proteins that are secreted by Vibrio cholerae. One of the PhoA+ mutants isolated showed a dramatic reduction in its ability to colonize the intestines of suckling mice. This mutant no longer produced a 20.5-kDa protein (TcpA) that we show is the major subunit of a V. cholerae pilus. Amino-terminal sequence analysis of the TcpA pilus subunit showed that it shares amino acid homology with the pilins produced by several other pathogenic bacteria. The TcpA pilus was coordinately expressed with cholera toxin under various culture conditions, and this effect appeared to be dependent on the transcriptional activator encoded by the toxR gene. We conclude that the toxR gene plays a central role in the transcriptional regulation of multiple virulence genes of V. cholerae.

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Migration: the biology of life on the move

2015-05-20

Hugh Dingle

PART ONE: MIGRATION AND METHODS FOR ITS STUDY PART TWO: PROXIMATE FACTORS IN MIGRATION PART THREE: MIGRATORY LIFE HISTORIES AND THEIR EVOLUTION PART FOUR: MIGRATION AND HUMAN BIOLOGY PART ONE: MIGRATION AND METHODS FOR ITS STUDY PART TWO: PROXIMATE FACTORS IN MIGRATION PART THREE: MIGRATORY LIFE HISTORIES AND THEIR EVOLUTION PART FOUR: MIGRATION AND HUMAN BIOLOGY

Global Climate and Infectious Disease: The Cholera Paradigm

1996-12-20

Rita R. Colwell

The origin of cholera has been elusive, even though scientific evidence clearly shows it is a waterborne disease. However, standard bacteriological procedures for isolation of the cholera vibrio from environmental … The origin of cholera has been elusive, even though scientific evidence clearly shows it is a waterborne disease. However, standard bacteriological procedures for isolation of the cholera vibrio from environmental samples, including water, between epidemics generally were unsuccessful. Vibrio cholerae , a marine vibrio, requiring salt for growth, enters into a dormant, viable but nonculturable stage when conditions are unfavorable for growth and reproduction. The association of Vibrio cholerae with plankton, notably copepods, provides further evidence for the environmental origin of cholera, as well as an explanation for the sporadic and erratic occurrence of cholera epidemics. On a global scale, cholera epidemics can now be related to climate and climatic events, such as El Niño, as well as the global distribution of the plankton host. Remote sensing, with the use of satellite imagery, offers the potential for predicting conditions conducive to cholera outbreaks or epidemics.

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Quorum-sensing regulators control virulence gene expression in Vibrio cholerae

2002-02-19

Jun Zhu , Melissa B. Miller , Russell E. Vance +3 more

The production of virulence factors including cholera toxin and the toxin-coregulated pilus in the human pathogen Vibrio cholerae is strongly influenced by environmental conditions. The well-characterized ToxR signal transduction cascade … The production of virulence factors including cholera toxin and the toxin-coregulated pilus in the human pathogen Vibrio cholerae is strongly influenced by environmental conditions. The well-characterized ToxR signal transduction cascade is responsible for sensing and integrating the environmental information and controlling the virulence regulon. We show here that, in addition to the known components of the ToxR signaling circuit, quorum-sensing regulators are involved in regulation of V. cholerae virulence. We focused on the regulators LuxO and HapR because homologues of these two proteins control quorum sensing in the closely related luminous marine bacterium Vibrio harveyi . Using an infant mouse model, we found that a luxO mutant is severely defective in colonization of the small intestine. Gene arrays were used to profile transcription in the V. cholerae wild type and the luxO mutant. These studies revealed that the ToxR regulon is repressed in the luxO mutant, and that this effect is mediated by another negative regulator, HapR. We show that LuxO represses hapR expression early in log-phase growth, and constitutive expression of hapR blocks ToxR-regulon expression. Additionally, LuxO and HapR regulate a variety of other cellular processes including motility, protease production, and biofilm formation. Together these data suggest a role for quorum sensing in modulating expression of blocks of virulence genes in a reciprocal fashion in vivo .

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Genetic Exchange between Bacteria in the Environment

1999-09-01

John Davison

Oxygen-Dependent Microbial Killing by Phagocytes

1978-03-23

Bernard Babior

THE part played by phagocytes in defense against invading pathogens has been recognized since 1883. In that year, Metschnikoff, a Russian zoologist, reported that foreign particles injected into metazoans (in … THE part played by phagocytes in defense against invading pathogens has been recognized since 1883. In that year, Metschnikoff, a Russian zoologist, reported that foreign particles injected into metazoans (in Metschnikoff's experiments, starfish larvae) were taken up by a population of "wandering mesodermal cells" that resided in interstitial tissues.1 He postulated a crucial role in host defense for these wandering cells, which he named "phagocytes." Since Metschnikoff's discovery, hundreds of scientists studying dozens of species have reported thousands of studies on these cells, perhaps the most widely recognized of which are those of the eminent English physician Sir Colenso Ridgeon . . .

Vibrio harveyi: a significant pathogen of marine vertebrates and invertebrates

2006-07-06

Brian Austin , Xiaohong Zhang

Journal Article Vibrio harveyi: a significant pathogen of marine vertebrates and invertebrates Get access B. Austin, B. Austin School of Life Sciences, John Muir Building, Heriot‐Watt University, Riccarton, Edinburgh, UK … Journal Article Vibrio harveyi: a significant pathogen of marine vertebrates and invertebrates Get access B. Austin, B. Austin School of Life Sciences, John Muir Building, Heriot‐Watt University, Riccarton, Edinburgh, UK Brian Austin, School of Life Sciences, John Muir Building, Heriot‐Watt University, Riccarton, Edinburgh EH14 4AS, UK. E‐mail: [email protected] Search for other works by this author on: Oxford Academic Google Scholar X‐H. Zhang X‐H. Zhang Department of Marine Biology, Ocean University of China, Qingdao, China Search for other works by this author on: Oxford Academic Google Scholar Letters in Applied Microbiology, Volume 43, Issue 2, 1 August 2006, Pages 119–124, https://doi.org/10.1111/j.1472-765X.2006.01989.x Published: 01 August 2006 Article history Received: 29 May 2006 Revision received: 01 June 2006 Accepted: 01 June 2006 Published: 01 August 2006

Evidence for several waves of global transmission in the seventh cholera pandemic

2011-08-24

Ankur Mutreja , Dong Wook Kim , Nicholas R. Thomson +7 more

Molecular Mechanisms of Bacterial Virulence Elucidated Using a Pseudomonas aeruginosa– Caenorhabditis elegans Pathogenesis Model

1999-01-01

Shalina Mahajan‐Miklos , Man‐Wah Tan , Laurence G. Rahme +1 more

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Mg2+ as an Extracellular Signal: Environmental Regulation of Salmonella Virulence

1996-01-01

Eleonora Garcı́a Véscovi , Fernando C. Soncini , Eduardo A. Groisman

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Integrons: agents of bacterial evolution

2006-07-17

Didier Mazel

Vibrio parahaemolyticus: A concern of seafood safety

2007-02-02

Yi‐Cheng Su , Chengchu Liu

Lipocalin 2 mediates an innate immune response to bacterial infection by sequestrating iron

2004-11-07

Trude H. Flo , Kelly D. Smith , Shintaro Sato +5 more

Recent findings on the viable but nonculturable state in pathogenic bacteria

2009-11-24

James D. Oliver

Many bacteria, including a variety of important human pathogens, are known to respond to various environmental stresses by entry into a novel physiological state, where the cells remain viable, but … Many bacteria, including a variety of important human pathogens, are known to respond to various environmental stresses by entry into a novel physiological state, where the cells remain viable, but are no longer culturable on standard laboratory media. On resuscitation from this 'viable but nonculturable' (VBNC) state, the cells regain culturability and the renewed ability to cause infection. It is likely that the VBNC state is a survival strategy, although several interesting alternative explanations have been suggested. This review describes the VBNC state, the various chemical and physical factors known to induce cells into this state, the cellular traits and gene expression exhibited by VBNC cells, their antibiotic resistance, retention of virulence and ability to attach and persist in the environment, and factors that have been found to allow resuscitation of VBNC cells. Along with simple reversal of the inducing stresses, a variety of interesting chemical and biological factors have been shown to allow resuscitation, including extracellular resuscitation-promoting proteins, a novel quorum-sensing system (AI-3) and interactions with amoeba. Finally, the central role of catalase in the VBNC response of some bacteria, including its genetic regulation, is described.

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CENSUS AND CONSENSUS IN BACTERIAL ECOSYSTEMS: The LuxR-LuxI Family of Quorum-Sensing Transcriptional Regulators

1996-10-01

Clay Fuqua , Stephen C. Winans , E. Peter Greenberg

The importance of accurate demographic information is reflected in the United States Constitution, Article 1, which provides for a decennial census of this country's human population. Bacteria also conduct a … The importance of accurate demographic information is reflected in the United States Constitution, Article 1, which provides for a decennial census of this country's human population. Bacteria also conduct a census of their population and do so more frequently, more efficiently, and as far we know, with little if any of the political contentiousness caused by human demographers. Many examples have been found of particular bacterial genes, operons, or regulons that are expressed preferentially at high cell densities. Many of these are regulated by proteins related to the LuxR and LuxI proteins of Vibrio fischeri, and by a diffusible pheromone called an autoinducer. LuxR and LuxI and their cognate autoinducer (3-oxohexanoyl homoserine lactone, designated VAI-1) provide an important model to describe the functions of this family of proteins. LuxR is a VAI-1 receptor and a VAI-1–dependent transcriptional activator, and LuxI directs the synthesis of VAI-1. VAI-1 diffuses across the bacterial envelope, and intracellular concentrations of it are therefore strongly increased by nearby VAI-1–producing bacteria. Similar systems regulate pathogenesis factors in Pseudomonas aeruginosa and Erwinia spp., as well as Ti plasmid conjugal transfer in Agrobacterium tumefaciens, and many other genes in numerous genera of gram-negative bacteria. Genetic analyses of these systems have revealed a high degree of functional conservation, while also uncovering features that are unique to each.

DNA sequence of both chromosomes of the cholera pathogen Vibrio cholerae

2000-08-01

John F. Heidelberg , Jonathan A. Eisen , William Nelson +7 more

Here we determine the complete genomic sequence of the Gram negative, γ-Proteobacterium Vibrio cholerae El Tor N16961 to be 4,033,460 base pairs (bp). The genome consists of two circular chromosomes … Here we determine the complete genomic sequence of the Gram negative, γ-Proteobacterium Vibrio cholerae El Tor N16961 to be 4,033,460 base pairs (bp). The genome consists of two circular chromosomes of 2,961,146 bp and 1,072,314 bp that together encode 3,885 open reading frames. The vast majority of recognizable genes for essential cell functions (such as DNA replication, transcription, translation and cell-wall biosynthesis) and pathogenicity (for example, toxins, surface antigens and adhesins) are located on the large chromosome. In contrast, the small chromosome contains a larger fraction (59%) of hypothetical genes compared with the large chromosome (42%), and also contains many more genes that appear to have origins other than the γ-Proteobacteria. The small chromosome also carries a gene capture system (the integron island) and host ‘addiction’ genes that are typically found on plasmids; thus, the small chromosome may have originally been a megaplasmid that was captured by an ancestral Vibrio species. The V. cholerae genomic sequence provides a starting point for understanding how a free-living, environmental organism emerged to become a significant human bacterial pathogen.

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A Virulence Locus of Pseudomonas aeruginosa Encodes a Protein Secretion Apparatus

2006-06-08

Joseph D. Mougous , M.E. Cuff , Stefan Raunser +7 more

Bacterial pathogens frequently use protein secretion to mediate interactions with their hosts. Here we found that a virulence locus (HSI-I) of Pseudomonas aeruginosa encodes a protein secretion apparatus. The apparatus … Bacterial pathogens frequently use protein secretion to mediate interactions with their hosts. Here we found that a virulence locus (HSI-I) of Pseudomonas aeruginosa encodes a protein secretion apparatus. The apparatus assembled in discrete subcellular locations and exported Hcp1, a hexameric protein that forms rings with a 40 angstrom internal diameter. Regulatory patterns of HSI-I suggested that the apparatus functions during chronic infections. We detected Hcp1 in pulmonary secretions of cystic fibrosis (CF) patients and Hcp1-specific antibodies in their sera. Thus, HSI-I likely contributes to the pathogenesis of P. aeruginosa in CF patients. HSI-I-related loci are widely distributed among bacterial pathogens and may play a general role in mediating host interactions.

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Epidemiology, Genetics, and Ecology of Toxigenic Vibrio cholerae

1998-12-01

Shah M. Faruque , M. John Albert , John J. Mekalanos

SUMMARY Cholera caused by toxigenic Vibrio cholerae is a major public health problem confronting developing countries, where outbreaks occur in a regular seasonal pattern and are particularly associated with poverty … SUMMARY Cholera caused by toxigenic Vibrio cholerae is a major public health problem confronting developing countries, where outbreaks occur in a regular seasonal pattern and are particularly associated with poverty and poor sanitation. The disease is characterized by a devastating watery diarrhea which leads to rapid dehydration, and death occurs in 50 to 70% of untreated patients. Cholera is a waterborne disease, and the importance of water ecology is suggested by the close association of V. cholerae with surface water and the population interacting with the water. Cholera toxin (CT), which is responsible for the profuse diarrhea, is encoded by a lysogenic bacteriophage designated CTXΦ. Although the mechanism by which CT causes diarrhea is known, it is not clear why V. cholerae should infect and elaborate the lethal toxin in the host. Molecular epidemiological surveillance has revealed clonal diversity among toxigenic V. cholerae strains and a continual emergence of new epidemic clones. In view of lysogenic conversion by CTXΦ as a possible mechanism of origination of new toxigenic clones of V. cholerae, it appears that the continual emergence of new toxigenic strains and their selective enrichment during cholera outbreaks constitute an essential component of the natural ecosystem for the evolution of epidemic V. cholerae strains and genetic elements that mediate the transfer of virulence genes. The ecosystem comprising V. cholerae, CTXΦ, the aquatic environment, and the mammalian host offers an understanding of the complex relationship between pathogenesis and the natural selection of a pathogen.

Siderophore-Based Iron Acquisition and Pathogen Control

2007-09-01

Marcus Miethke , Mohamed A. Marahiel

High-affinity iron acquisition is mediated by siderophore-dependent pathways in the majority of pathogenic and nonpathogenic bacteria and fungi. Considerable progress has been made in characterizing and understanding mechanisms of siderophore … High-affinity iron acquisition is mediated by siderophore-dependent pathways in the majority of pathogenic and nonpathogenic bacteria and fungi. Considerable progress has been made in characterizing and understanding mechanisms of siderophore synthesis, secretion, iron scavenging, and siderophore-delivered iron uptake and its release. The regulation of siderophore pathways reveals multilayer networks at the transcriptional and posttranscriptional levels. Due to the key role of many siderophores during virulence, coevolution led to sophisticated strategies of siderophore neutralization by mammals and (re)utilization by bacterial pathogens. Surprisingly, hosts also developed essential siderophore-based iron delivery and cell conversion pathways, which are of interest for diagnostic and therapeutic studies. In the last decades, natural and synthetic compounds have gained attention as potential therapeutics for iron-dependent treatment of infections and further diseases. Promising results for pathogen inhibition were obtained with various siderophore-antibiotic conjugates acting as "Trojan horse" toxins and siderophore pathway inhibitors. In this article, general aspects of siderophore-mediated iron acquisition, recent findings regarding iron-related pathogen-host interactions, and current strategies for iron-dependent pathogen control will be reviewed. Further concepts including the inhibition of novel siderophore pathway targets are discussed.

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Secretion systems in Gram-negative bacteria: structural and mechanistic insights

2015-05-15

Tiago R. D. Costa , Catarina Felisberto‐Rodrigues , Amit Meir +4 more

INFECTIVE HEREDITY OF MULTIPLE DRUG RESISTANCE IN BACTERIA

1963-03-01

Tsutomu Watanabe

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A Type VI Secretion System of Pseudomonas aeruginosa Targets a Toxin to Bacteria

2010-01-01

Rachel D. Hood , Pragya Singh , FoSheng Hsu +7 more

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Lateral gene transfer and the nature of bacterial innovation

2000-05-01

Howard Ochman , Jeffrey G. Lawrence , Eduardo A. Groisman

Chemiosmotic Mechanism of Antimicrobial Activity of Ag + in Vibrio cholerae

2002-07-28

Pavel Dibrov , Judith Dzioba , Khoosheh K. Gosink +1 more

Although the antimicrobial effects of silver salts were noticed long ago, the molecular mechanism of the bactericidal action of Ag(+) in low concentrations has not been elucidated. Here, we show … Although the antimicrobial effects of silver salts were noticed long ago, the molecular mechanism of the bactericidal action of Ag(+) in low concentrations has not been elucidated. Here, we show that low concentrations of Ag(+) induce a massive proton leakage through the Vibrio cholerae membrane, which results in complete deenergization and, with a high degree of probability, cell death.

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Genome sequence of Vibrio parahaemolyticus: a pathogenic mechanism distinct from that of V cholerae

2003-03-01

Kozo Makino , Kenshiro Oshima , Ken Kurokawa +7 more

Bacterial osmoadaptation: the role of osmolytes in bacterial stress and virulence

2002-03-01

Roy D. Sleator , Colin Hill

Two general strategies exist for the growth and survival of prokaryotes in environments of elevated osmolarity. The 'salt in cytoplasm' approach, which requires extensive structural modifications, is restricted mainly to … Two general strategies exist for the growth and survival of prokaryotes in environments of elevated osmolarity. The 'salt in cytoplasm' approach, which requires extensive structural modifications, is restricted mainly to members of the Halobacteriaceae. All other species have convergently evolved to cope with environments of elevated osmolarity by the accumulation of a restricted range of low molecular mass molecules, termed compatible solutes owing to their compatibility with cellular processes at high internal concentrations. Herein we review the molecular mechanisms governing the accumulation of these compounds, both in Gram-positive and Gram-negative bacteria, focusing specifically on the regulation of their transport/synthesis systems and the ability of these systems to sense and respond to changes in the osmolarity of the extracellular environment. Finally, we examine the current knowledge on the role of these osmostress responsive systems in contributing to the virulence potential of a number of pathogenic bacteria.

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Effects of Global Climate on Infectious Disease: the Cholera Model

2002-10-01

Erin K. Lipp , Anwar Huq , Rita R. Colwell

SUMMARY Recently, the role of the environment and climate in disease dynamics has become a subject of increasing interest to microbiologists, clinicians, epidemiologists, and ecologists. Much of the interest has … SUMMARY Recently, the role of the environment and climate in disease dynamics has become a subject of increasing interest to microbiologists, clinicians, epidemiologists, and ecologists. Much of the interest has been stimulated by the growing problems of antibiotic resistance among pathogens, emergence and/or reemergence of infectious diseases worldwide, the potential of bioterrorism, and the debate concerning climate change. Cholera, caused by Vibrio cholerae , lends itself to analyses of the role of climate in infectious disease, coupled to population dynamics of pathogenic microorganisms, for several reasons. First, the disease has a historical context linking it to specific seasons and biogeographical zones. In addition, the population dynamics of V. cholerae in the environment are strongly controlled by environmental factors, such as water temperature, salinity, and the presence of copepods, which are, in turn, controlled by larger-scale climate variability. In this review, the association between plankton and V. cholerae that has been documented over the last 20 years is discussed in support of the hypothesis that cholera shares properties of a vector-borne disease. In addition, a model for environmental transmission of cholera to humans in the context of climate variability is presented. The cholera model provides a template for future research on climate-sensitive diseases, allowing definition of critical parameters and offering a means of developing more sophisticated methods for prediction of disease outbreaks.

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Biodiversity of Vibrios

2004-09-01

Fabiano L. Thompson , Tetsuya Iida , Jean Swings

SUMMARY Vibrios are ubiquitous and abundant in the aquatic environment. A high abundance of vibrios is also detected in tissues and/or organs of various marine algae and animals, e.g., abalones, … SUMMARY Vibrios are ubiquitous and abundant in the aquatic environment. A high abundance of vibrios is also detected in tissues and/or organs of various marine algae and animals, e.g., abalones, bivalves, corals, fish, shrimp, sponges, squid, and zooplankton. Vibrios harbour a wealth of diverse genomes as revealed by different genomic techniques including amplified fragment length polymorphism, multilocus sequence typing, repetetive extragenic palindrome PCR, ribotyping, and whole-genome sequencing. The 74 species of this group are distributed among four different families, i.e., Enterovibrionaceae , Photobacteriaceae , Salinivibrionaceae , and Vibrionaceae . Two new genera, i.e., Enterovibrio norvegicus and Grimontia hollisae , and 20 novel species, i.e., Enterovibrio coralii , Photobacterium eurosenbergii , V. brasiliensis , V. chagasii , V. coralliillyticus , V. crassostreae , V. fortis , V. gallicus , V. hepatarius , V. hispanicus , V. kanaloaei , V. neonatus , V. neptunius , V. pomeroyi , V. pacinii , V. rotiferianus , V. superstes , V. tasmaniensis , V. ezurae , and V. xuii , have been described in the last few years. Comparative genome analyses have already revealed a variety of genomic events, including mutations, chromosomal rearrangements, loss of genes by decay or deletion, and gene acquisitions through duplication or horizontal transfer (e.g., in the acquisition of bacteriophages, pathogenicity islands, and super-integrons), that are probably important driving forces in the evolution and speciation of vibrios. Whole-genome sequencing and comparative genomics through the application of, e.g., microarrays will facilitate the investigation of the gene repertoire at the species level. Based on such new genomic information, the taxonomy and the species concept for vibrios will be reviewed in the next years.

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The Origin of the Haitian Cholera Outbreak Strain

2010-12-09

Chen-Shan Chin , Jon M. Sorenson , Jason B. Harris +7 more

Although cholera has been present in Latin America since 1991, it had not been epidemic in Haiti for at least 100 years. Recently, however, there has been a severe outbreak … Although cholera has been present in Latin America since 1991, it had not been epidemic in Haiti for at least 100 years. Recently, however, there has been a severe outbreak of cholera in Haiti.We used third-generation single-molecule real-time DNA sequencing to determine the genome sequences of 2 clinical Vibrio cholerae isolates from the current outbreak in Haiti, 1 strain that caused cholera in Latin America in 1991, and 2 strains isolated in South Asia in 2002 and 2008. Using primary sequence data, we compared the genomes of these 5 strains and a set of previously obtained partial genomic sequences of 23 diverse strains of V. cholerae to assess the likely origin of the cholera outbreak in Haiti.Both single-nucleotide variations and the presence and structure of hypervariable chromosomal elements indicate that there is a close relationship between the Haitian isolates and variant V. cholerae El Tor O1 strains isolated in Bangladesh in 2002 and 2008. In contrast, analysis of genomic variation of the Haitian isolates reveals a more distant relationship with circulating South American isolates.The Haitian epidemic is probably the result of the introduction, through human activity, of a V. cholerae strain from a distant geographic source. (Funded by the National Institute of Allergy and Infectious Diseases and the Howard Hughes Medical Institute.).

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The Bacterial Glycocalyx in Nature and Disease

1981-10-01

J. William Costerton , Randall T. Irvin , K.-J. Cheng

Human coronavirus (HCoV) infection causes respiratory diseases with mild to severe outcomes. In the last 15 years, we have witnessed the emergence of two zoonotic, highly pathogenic HCoVs: severe acute … Human coronavirus (HCoV) infection causes respiratory diseases with mild to severe outcomes. In the last 15 years, we have witnessed the emergence of two zoonotic, highly pathogenic HCoVs: severe acute respiratory syndrome coronavirus (SARS-CoV) and ...Read More

Bacterial Secretion Systems: An Overview

2016-01-29

Erin R. Green , Joan Mecsas

ABSTRACT Bacterial pathogens utilize a multitude of methods to invade mammalian hosts, damage tissue sites, and thwart the immune system from responding. One essential component of these strategies for many … ABSTRACT Bacterial pathogens utilize a multitude of methods to invade mammalian hosts, damage tissue sites, and thwart the immune system from responding. One essential component of these strategies for many bacterial pathogens is the secretion of proteins across phospholipid membranes. Secreted proteins can play many roles in promoting bacterial virulence, from enhancing attachment to eukaryotic cells, to scavenging resources in an environmental niche, to directly intoxicating target cells and disrupting their functions. Many pathogens use dedicated protein secretion systems to secrete virulence factors from the cytosol of the bacteria into host cells or the host environment. In general, bacterial protein secretion apparatuses can be divided into classes, based on their structures, functions, and specificity. Some systems are conserved in all classes of bacteria and secrete a broad array of substrates, while others are only found in a small number of bacterial species and/or are specific to only one or a few proteins. In this chapter, we review the canonical features of several common bacterial protein secretion systems, as well as their roles in promoting the virulence of bacterial pathogens. Additionally, we address recent findings that indicate that the innate immune system of the host can detect and respond to the presence of protein secretion systems during mammalian infection.

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Persistent bacterial infections and persister cells

2017-05-22

Robert A. Fisher , Bridget Gollan , Sophie Hélaine

Mode of Communication of Cholera.

1855-04-01

E.A. Parkes

Cholera

1995-01-01

James B. Kaper , J. Glenn Morris , M. M. Levine

Despite more than a century of study, cholera still presents challenges and surprises to us. Throughout most of the 20th century, cholera was caused by Vibrio cholerae of the O1 … Despite more than a century of study, cholera still presents challenges and surprises to us. Throughout most of the 20th century, cholera was caused by Vibrio cholerae of the O1 serogroup and the disease was largely confined to Asia and Africa. However, the last decade of the 20th century has witnessed two major developments in the history of this disease. In 1991, a massive outbreak of cholera started in South America, the one continent previously untouched by cholera in this century. In 1992, an apparently new pandemic caused by a previously unknown serogroup of V. cholerae (O139) began in India and Bangladesh. The O139 epidemic has been occurring in populations assumed to be largely immune to V. cholerae O1 and has rapidly spread to many countries including the United States. In this review, we discuss all aspects of cholera, including the clinical microbiology, epidemiology, pathogenesis, and clinical features of the disease. Special attention will be paid to the extraordinary advances that have been made in recent years in unravelling the molecular pathogenesis of this infection and in the development of new generations of vaccines to prevent it.

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Cholera

2004-01-01

David A. Sack , R. Bradley Sack , G. Balakrish Nair +1 more

Updated Global Burden of Cholera in Endemic Countries

2015-06-04

Mohammad Ali , Allyson R. Nelson , Anna Lena Lopez +1 more

Background The global burden of cholera is largely unknown because the majority of cases are not reported. The low reporting can be attributed to limited capacity of epidemiological surveillance and … Background The global burden of cholera is largely unknown because the majority of cases are not reported. The low reporting can be attributed to limited capacity of epidemiological surveillance and laboratories, as well as social, political, and economic disincentives for reporting. We previously estimated 2.8 million cases and 91,000 deaths annually due to cholera in 51 endemic countries. A major limitation in our previous estimate was that the endemic and non-endemic countries were defined based on the countries' reported cholera cases. We overcame the limitation with the use of a spatial modelling technique in defining endemic countries, and accordingly updated the estimates of the global burden of cholera. Methods/Principal Findings Countries were classified as cholera endemic, cholera non-endemic, or cholera-free based on whether a spatial regression model predicted an incidence rate over a certain threshold in at least three of five years (2008-2012). The at-risk populations were calculated for each country based on the percent of the country without sustainable access to improved sanitation facilities. Incidence rates from population-based published studies were used to calculate the estimated annual number of cases in endemic countries. The number of annual cholera deaths was calculated using inverse variance-weighted average case-fatality rate (CFRs) from literature-based CFR estimates. We found that approximately 1.3 billion people are at risk for cholera in endemic countries. An estimated 2.86 million cholera cases (uncertainty range: 1.3m-4.0m) occur annually in endemic countries. Among these cases, there are an estimated 95,000 deaths (uncertainty range: 21,000-143,000). Conclusion/Significance The global burden of cholera remains high. Sub-Saharan Africa accounts for the majority of this burden. Our findings can inform programmatic decision-making for cholera control.

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Distribution and Evolutionary Trajectories of β-Lactamases in Vibrio: Genomic Insights from CARB-Type Enzymes in the Harveyi and Cholerae Clades

2025-06-25

Yi Yang , Xingkun Jin , Zhe Zhao | Genome Biology and Evolution

Abstract Antibiotic resistance mediated by β-lactamases (BLs), encoded by bla genes, is a significant global health threat, necessitating systematic studies of their diversity and evolution, particularly among pathogenic bacteria lineages. … Abstract Antibiotic resistance mediated by β-lactamases (BLs), encoded by bla genes, is a significant global health threat, necessitating systematic studies of their diversity and evolution, particularly among pathogenic bacteria lineages. Leveraging over 6,000 quality-filtered Vibrio genomes alongside six newly sequenced marine symbiotic strains representing 128 nominal and 57 unclassified Vibrio species, our study extends taxonomic breadth and resolution for investigating BL diversity. We identified 4,431 BLs across 41 species, encompassing all four Ambler Classes (A∼D). Among these, CARBenicillin-hydrolyzing Class A BLs (CARBs encoded by blaCARB family) were the most prevalent (60.7%) and exhibited a clade-centric distribution particularly in Harveyi clade and V. cholerae, underscoring influence of specific ecological and evolutionary pressures. We refined CARB classification into two subfamilies: CARB-17-like (blaCARB-17-like) confined to Harveyi clade, and CARB-1-like (blaCARB-1-like) found exclusively outside Harveyi clade, based on phylogenetic placement, sequence similarity, and inheritance patterns, providing a clearer framework for delineating their functional and phylogenetic nuances. Notably, blaCARB-17-like genes in non-pathogenic Harveyi Subclade II showed significantly relaxed selection, accompanied by unusual mutations within key conserved motifs especially catalytic serine residues, suggesting evolutionary drift that may compromise canonical enzymatic activity. Furthermore, blaCARB-17-like genes, present as a single copy, emerged as a core gene in Harveyi clade, showing promise as a diagnostic marker for clinically significant Harveyi clade species, despite limited yet significant interspecies genetic exchanges mediated by recombination or mobile genetic elements. Our study advances the understanding of BL evolution and genomic distribution in Vibrio, with broad implications for diagnostic applications and resistance management strategies.

Killed whole-cell cholera vaccines: is the evidence sufficient for their widespread use?

2025-06-25

Mohammod Jobayer Chisti | The Lancet Global Health

Protection from killed whole-cell cholera vaccines: a systematic review and meta-analysis

2025-06-25

Hanmeng Xu , Amanda Tiffany , Francisco J. Luquero +7 more | The Lancet Global Health

Hybridization capture sequencing for Vibrio spp. and associated virulence factors

2025-06-25

Kyle D. Brumfield , Sana Enke , Brandon K. Swan +7 more | mBio

ABSTRACT Proliferation of Vibrio spp. in aquatic ecosystems is associated with climate change and, concomitantly, increased incidence of vibriosis. They are autochthonous to aquatic environments globally, but traditional metagenomic methods … ABSTRACT Proliferation of Vibrio spp. in aquatic ecosystems is associated with climate change and, concomitantly, increased incidence of vibriosis. They are autochthonous to aquatic environments globally, but traditional metagenomic methods for detecting and typing pathogenic Vibrio spp. are challenged by their presence in relatively low abundance and ability to persist in a viable but nonculturable state. In the study reported here, hybridization capture sequencing (HCS) was employed to profile low-abundance Vibrio spp. in environmental samples. The HCS panel targeted a family of molecular chaperones (CPN60) specific to 69 Vibrio spp. and 162 Vibrio -specific virulence factors. This approach was evaluated in parallel with traditional whole-community shotgun sequencing in a metagenomic analysis of water and oyster samples collected from the Chesapeake Bay. In addition, Vibrio parahaemolyticus and Vibrio vulnificus strains isolated from the samples were subjected to whole-genome sequencing to determine the genetic characteristics of pathogenic Vibrio spp. circulating in an aquatic environment. HCS, employed to determine the incidence and characterization of specific Vibrio spp., yielded significantly greater metagenomic insight, notably a variety of other Vibrio spp., including detection of Vibrio cholerae , Vibrio fluvialis , and Vibrio aestuarianus , in addition to Vibrio parahaemolyticus and Vibrio vulnificus , and also important virulence factors not detectable using traditional molecular methods. Thus, pathogenic Vibrio spp. in aquatic ecosystems may be far more common than currently understood. It is concluded that environmental surveillance should include HCS, a valuable tool for the detection and characterization of pathogenic agents in aquatic ecosystems, notably vibrios. IMPORTANCE The increasing prevalence of pathogenic Vibrio spp. in aquatic ecosystems, driven by climate change, is closely linked to a rise in cholera and vibriosis cases, emphasizing the need for improved environmental surveillance. Vibrios are naturally occurring in aquatic environments globally, but traditional metagenomic methods for detecting and typing pathogenic Vibrio spp. are challenged by their presence in relatively low abundance and ability to persist in a viable but nonculturable state. In the study reported here, hybridization capture sequencing was employed to profile low-abundance Vibrio spp. in metagenomic samples, namely water and oysters collected from the Chesapeake Bay. This approach was evaluated in parallel with traditional whole-community shotgun sequencing and whole-genome sequencing of Vibrio parahaemolyticus and Vibrio vulnificus strains isolated from the samples. Results suggest pathogenic Vibrio spp. in aquatic ecosystems may be far more common than currently understood, when multiple methods are considered for environmental surveillance.

First Case of Infective Endocarditis Caused by Vibrio metschnikovii: Clinico-Diagnostic Complexities and a Systematic Literature Review

2025-06-25

Alessandro Carrozzo , Vittorio Bolcato , Luigi Martinelli +4 more | Clinics and Practice

Background: Non-cholera Vibrio species are rare waterborne pathogens that can cause severe infections. Among these, few cases of Vibrio metschnikovii infections have been reported, especially in the gastrointestinal tract, with … Background: Non-cholera Vibrio species are rare waterborne pathogens that can cause severe infections. Among these, few cases of Vibrio metschnikovii infections have been reported, especially in the gastrointestinal tract, with no cardiac tissue involvement as a result. Following the PRISMA checklist, we conducted a literature review, and thirteen articles for twenty-two cases overall were included: seven cases of sepsis (in three cases, the echocardiographic results were negative), seven cases of pneumonia, two skin infections, eleven cases of diarrhoea, and a gastroenteritis outbreak. This report documents the expanding clinical spectrum and the role played by V. metschnikovii in infective endocarditis. Case report: A 28-year-old male patient was referred to the cardiac surgery unit for urgent mitral valve replacement due to suspicion of infective endocarditis. Microbiological tests yielded negative results. Following recovery and discharge with antimicrobial therapy for 6 weeks, the patient experienced prosthesis detachment, necessitating re-hospitalisation for an emergency valve replacement. Vibrio metschnikovii was identified on the prosthesis valve through PCR and successfully treated with ciprofloxacin. However, a spontaneous rupture of the ascending thoracic aorta led to a neurological injury. Discussion: This case represents the first case of valve infection caused by Vibrio metschnikovii, characterised by diagnostic and therapeutic challenges and the involvement of the great vessels. Also considered in this case, for a disease with a median age of 58 years (11–83) and a male-to-female ratio of 2.2, were one male neonate and six cases for whom neither sex nor age was indicated. Excluding gastrointestinal cases, the septic forms are associated with high morbidity, although the single case described involved a young and healthy subject. Risk factors for the pathogen or predisposing/pathological conditions for endocarditis did not emerge. The routes and the time of infection could not be determined, deepening the possibility of occupational exposure via the patient’s position as a boat worker. Poor sensitivity to third-generation cephalosporins has been reported in the literature: the absence of an antibiogram does not allow for a comparison, although resolution was achieved with ciprofloxacin. Conclusion: The rising global incidence of non-cholera Vibrio infections, driven by environmental changes, calls for urgent research into the factors behind their pathogenicity and infection routes. Diagnostic complexities have emerged together with clinical severity.

Genomic insights into clinical non-O1/non-O139 Vibrio cholera e isolates in Japan

2025-06-24

Yohei Kobayashi , Masato Suzuki , Shuntaro Umeda +4 more | Microbiology Spectrum

Non-O1/non-O139 Vibrio cholerae (NOVC) causes sporadic intestinal infections and systemic symptoms. Recently, global warming has led to an increase in NOVC infections; however, there have been no reports on the … Non-O1/non-O139 Vibrio cholerae (NOVC) causes sporadic intestinal infections and systemic symptoms. Recently, global warming has led to an increase in NOVC infections; however, there have been no reports on the genomic analysis of clinical NOVC isolates in Japan, and the molecular understanding of NOVC remains inadequate. We identified three cases of NOVC infection in Nagoya, Japan, in 2020 and performed genomic analysis to reveal the molecular characteristics of these isolates and compared them with those of previously reported clinical cases. Phylogenetic analysis revealed high diversity. This result indicates that the three cases were sporadic within the area over a short period of time from multiple contaminated sources. However, most clinical isolates carried virulence factor genes encoding El Tor type hemolysin, type VI secretion system (T6SS), and repeats-in-toxin toxin, and approximately half of the isolates carried nanH encoded on VPI-2, as well as the type III secretion system (T3SS). Additionally, detailed whole-genome sequencing (WGS) analysis revealed various types of T3SS, T6SS, VPI-2, and VSP-2. Variations in the number of Rep1 units of VopM were observed in the T3SS of the NOVC isolates in this study. The T6SS type identified in this study consisted of a large cluster and auxiliary clusters, showing diversity among the NOVC isolates. We recommend continued monitoring of clinical NOVC isolates as horizontal transmission along with host and environmental recombination may lead to changes in virulence.IMPORTANCEAlthough reports of non-O1/non-O139 Vibrio cholerae (NOVC) infections are rare, their actual incidence remains uncertain. This is partly due to nonspecific symptoms, the absence of a surveillance system in most countries including Japan, and the lack of appropriate laboratory culture techniques. However, NOVCs in the environment are increasing due to global warming, and the risk of NOVC infections is increasing. In this study, we conducted a comprehensive genomic analysis of clinical NOVC isolates from a city in Japan and compared their virulence factor profiles with those of previously reported clinical isolates using whole-genome sequencing (WGS). This result indicates that some sporadic cases have occurred in the area, suggesting that there are multiple sources of NOVC infection. The accumulation of such data will enhance our understanding of the pathogenicity of NOVCs and improve diagnostic accuracy.

Vibrio cholerae O1 El Tor A1552 encodes two functional ornithine lipid synthases and induces ornithine lipid formation under low phosphate and under low salinity growth conditions

2025-06-24

Miguel Ángel Vences‐Guzmán , Roberto Jhonatan Olea‐Ozuna , Raquel Martínez-Méndez +5 more | PLoS ONE

Ornithine lipids (OLs) are phosphorus-free membrane lipids that can be formed by a wide range of bacteria. The presence of OLs is frequently related to the resistance to abiotic stress … Ornithine lipids (OLs) are phosphorus-free membrane lipids that can be formed by a wide range of bacteria. The presence of OLs is frequently related to the resistance to abiotic stress conditions, and their synthesis is often induced as part of various stress responses. Two different pathways for synthesizing OLs are currently known: the OlsBA pathway, first described in Sinorhizobium meliloti, and the OlsF pathway, first described in Serratia proteamaculans. We identified in the genome of Vibrio cholerae O1 El Tor A1552 two genes encoding OlsF homologs, VC0489 is located on chromosome 1, whereas VCA0646 is located on chromosome 2. Both synthases, when expressed in Escherichia coli, caused the synthesis of OLs. Single mutants deficient in each of the OL synthases, double mutants deficient in both OL synthases, and mutants deficient in the transcriptional regulator PhoB were constructed and characterized. We corroborated that VC0489 is solely responsible for the synthesis of OLs under phosphate limitation. The deletion of VC0489 reduced the growth velocity compared to the wildtype under phosphate-limiting conditions but not under phosphate-replete conditions. The expression of VCA0646 is favored under low salt growth conditions, and its deletion abrogates OL synthesis at low salinities. The absence of VCA0646 and, therefore, the lack of OLs under low salt conditions makes the respective mutant more susceptible to polymyxin than OL-forming strains under these conditions. None of the mutants was affected in biofilm formation, swimming, or virulence assays using standardized survival assays with Caenorhabditis elegans or Galleria mellonella. Here, we describe two functional OL synthases present in a single bacterium for the first time, and we show evidence that OLs have an important function during the V. cholerae lifecycle.

Emergence and Prevalence of Vibrio cholerae O1 Sequence Type 75 Clonal Complex, Fujian Province, China, 2009–2023

2025-06-24

Zili Ke , Bo Pang , Jinsong Yang +5 more | Emerging infectious diseases

We investigated the molecular epidemiology of Vibrio cholerae O1 in Fujian Province, China, during 2009--2023. Sequence type (ST) 75 clonal complex has emerged continuously since 2020, and ST1480 and ST182 … We investigated the molecular epidemiology of Vibrio cholerae O1 in Fujian Province, China, during 2009--2023. Sequence type (ST) 75 clonal complex has emerged continuously since 2020, and ST1480 and ST182 have dominated. ST1480 strains appear to have widespread transmission. To monitor V. cholerae evolution, continued global genomic surveillance is needed.

Assessing Campylobacter jejuni Extracellular Vesicle–Host Interaction Using a Microfluidic Platform with Caco-2 Spheroides-on-Chip

2025-06-23

Silvia Tea Calzuola , Jeanne Malet-Villemagne , Debora Pinamonti +7 more | ACS Biomaterials Science & Engineering

Campylobacter jejuni is a foodborne pathogen that adheres to and invades the epithelial cells of the human intestinal tract. The extracellular vesicles (EVs) of C. jejuni have an important impact … Campylobacter jejuni is a foodborne pathogen that adheres to and invades the epithelial cells of the human intestinal tract. The extracellular vesicles (EVs) of C. jejuni have an important impact during pathogenicity, but their role in invasion of host intestinal epithelial cells remains largely unknown. In vitro models lack the complexity of tissue and fail to accurately replicate the dynamic interactions between EVs and human intestinal epithelial cells, while animal infection models have species-specific differences that limit their translational relevance and are associated with ethical concerns. To bridge this gap, we propose a microfluidic platform integrated with an impedimetric sensor to monitor C. jejuni EV interactions with human intestinal epithelial Caco-2 cells. When cultured in this microfluidic device, Caco-2 epithelial cells underwent spontaneous 3D morphogenesis into spheroid-like structures with diameters ranging from 50 to 100 μm. Functional assays revealed that the C. jejuni secretome and EVs (multiplicity of infection, MOI 10) caused a 60% reduction in Caco-2 cell viability in 2D plate cultures, as measured by the MTT assay. In contrast, 3D Caco-2 spheroids showed significantly increased resistance to cytotoxic effects of secreted virulence factors of C. jejuni. By combining impedance spectroscopy and live microscopic observation, the platform allowed real-time monitoring of cellular spatial growth and sensitive detection of EV interactions with intestinal epithelial cells, highlighting the protective role of 3D cell organization. The physiological relevance of the model was confirmed by TEER measurements that suggested that Campylobacter EVs diffused paracellularly. The developed microfluidic device is a promising platform for investigating host-microbe interactions and may have a broad impact on biomedical research on gastroenteritis.

Navigating the cholera elimination roadmap in Zambia – A scoping review (2013–2024)

2025-06-23

Nyuma Mbewe , John Tembo , Mpanga Kasonde +7 more | PLoS neglected tropical diseases

Cholera outbreaks are increasing in frequency and severity, particularly in Sub-Saharan Africa. Zambia, committed to ending cholera by 2025, instead experienced its most significant outbreak in 2024. This review examines … Cholera outbreaks are increasing in frequency and severity, particularly in Sub-Saharan Africa. Zambia, committed to ending cholera by 2025, instead experienced its most significant outbreak in 2024. This review examines the perceived regression in elimination efforts by addressing two questions: (i) What is known about cholera in Zambia? and (ii) What are the main suggested mechanisms and strategies to further elimination efforts in the region?. A scoping literature search was conducted in PUBMED to identify relevant qualitative and quantitative research studies published between 1st January 2013 and 30th June 2024 using the search terms 'cholera' and 'Zambia'. We identified 53 relevant publications. With the increasing influence of climate change, population growth, and rural-urban migration, further increases in outbreak frequency and magnitude are expected. Risk factors for recurrent outbreaks, including poor access to water, sanitation, and hygiene (WASH) services in unplanned urban settlements and rural fishing villages, continue to derail elimination efforts. Interventions are best planned at a decentralised, community-centric approach to prevent elimination and reintroduction at the district level. Pre-emptive vaccination campaigns before the rainy season and climate-resilient WASH infrastructure in cholera hotspots are also recommended. The goal to eliminate cholera by 2025 was unrealistic, as evidence points to the disease becoming endemic. Our findings confirm the need to align health and WASH investments with the Global Roadmap to Cholera Elimination by 2030 through a climate-focused lens. Recommendations for cholera elimination, including improved access to safe drinking water and sanitation, remain elusive in many low-income settings like Zambia. Patient-level information on survival and transmissibility is lacking. New research tailored to country-level solutions and enhancing community participation is urgently required. Insights from this review will be integrated into the next iteration of the National Cholera Control Plan and could apply to other countries with similar settings.

Draft genome sequence data of Vibrio cholerae responsible for cholera outbreaks in Ethiopia

2025-06-23

Abebaw Bitew Kifilie , Molalegne Bitew , Aschalew Gelaw +7 more | Microbiology Resource Announcements

Cholera is an acute diarrheal disease caused by Vibrio cholerae. Low-income countries, including Ethiopia, have been attacked by repeated outbreaks. Here, we present the draft genome sequence of V. cholerae … Cholera is an acute diarrheal disease caused by Vibrio cholerae. Low-income countries, including Ethiopia, have been attacked by repeated outbreaks. Here, we present the draft genome sequence of V. cholerae O1 strains isolated from clinical samples in Ethiopia.

Macrophage‐derived reactive oxygen species promote Salmonella aggresome formation contributing to bacterial antibiotic persistence

2025-06-22

Xiao Chen , Kefan Fang , Бо Ли +7 more | iMeta

Fish Health Management and Biosecurity Compliance in Some Fish Farms in the Southern Part of Lagos State, Nigeria

2025-06-21

Aladetohun Nike Funmilayo. , Sheo Odun- Onikosi , Israel Joshua Barde +4 more | Asian Journal of Fisheries and Aquatic Research

The study was an assessment of fish health management and biosecurity compliance in 62 fish farms in the southern part of Lagos State Nigeria. Cluster sampling was used in selecting … The study was an assessment of fish health management and biosecurity compliance in 62 fish farms in the southern part of Lagos State Nigeria. Cluster sampling was used in selecting the farmers in the study areas. Data was collected using well-structured questionnaires and interview. Descriptive and Chi square statistic was used for data presentation and analysis. The study revealed that majority of the respondents have attained tertiary education (63.5%), with 5 -9 years of experience in fish farming (75.8%). Majority of the fish farmers (66.7%) lack awareness of biosecurity. The sudy showed that all the respondents do not vaccinate their fish, do not use hand sanitizer and do not use specific protective clothing, respectively. Also all the respondents reported daily fish mortality ranging from 1-44 fish. This study concludes that there is a paucity of knowledge on fish health management systems and biosecurity measures which presents a serious threat to aquaculture production in the studied areas and poses a great risk of disease spread to neighbouring fish farms. This study recommends the development of a coordinated awareness campaigns on fish health manage‑ ment and biosecurity measures to fish farmers in the study areas, by fish pathologists and aquatic veterinarian. This can be done through seminars, workshops, conferences and advisory services, to ensure optimum fish production. The findings of this study will serve as a baseline information for fish farmers to adhere to strict biosecurity and biosafety measures in their fish farms to avoid the spread of diseases in their fish populations.

Isolation and characterization of Vibrio toranzoniae from adult Pacific oysters (Crassostrea gigas) in South Korea: Insights into pathogenicity and virulence factors

2025-06-21

Tiejun Song , Hyung‐Bae Jeon , Yu Chen +6 more | Journal of Invertebrate Pathology

An Integrated PMA Pretreatment Instrument for Simultaneous Quantitative Detection of Vibrio parahaemolyticus and Vibrio cholerae in Aquatic Products

2025-06-21

Yan Qin , Ranhua Xiong , Yong Zhao +2 more | Foods

Traditional hazard identification techniques for Vibrio parahaemolyticus often neglect the distinction between viable and nonviable bacteria in aquatic products, leading to overestimated disease risks and uncertainties in risk assessments. To … Traditional hazard identification techniques for Vibrio parahaemolyticus often neglect the distinction between viable and nonviable bacteria in aquatic products, leading to overestimated disease risks and uncertainties in risk assessments. To address this limitation, we developed an automated PMA pretreatment instrument that integrates dark incubation and photo-crosslinking into a unified workflow, allowing customizable parameters such as incubation time, light exposure duration, and mixing speed while maintaining stable temperatures (<±1 °C fluctuation) to preserve bacterial DNA integrity. Leveraging this system, a duplex qPCR assay was optimized for simultaneous quantitative detection of V. parahaemolyticus and V. cholerae in aquatic products and environmental samples. The assay demonstrated robust performance with 90–110% amplification efficiencies across diverse matrices, achieving low limits of detection (LODs) of 101–102 CFU/mL in shrimp farming environment water and 102–103 CFU/g in shrimp (Litopenaeus vannamei) and oyster (Crassostrea gigas). Notably, it effectively discriminated viable bacteria from 106 CFU/mL(g) nonviable cells and showed strong correlation with ISO-standard methods in real-world sample validation. This integrated platform offers a rapid, automated solution for accurate viable bacterial quantification, with significant implications for food safety, pathogen surveillance, and risk management in aquatic industries.

Bacteriological Analysis of Mini Buses in Effurun Delta State

2025-06-20

M.O. Emolade , Precious Onome Obiebi , Onyekachukwu Mabel ADINKWU +7 more | Advances in Research

Every human society depends on transportation. In most regions of the world, buses are a mode of transportation. Living in a society involves sharing numerous common areas, which allows a … Every human society depends on transportation. In most regions of the world, buses are a mode of transportation. Living in a society involves sharing numerous common areas, which allows a variety of germs that might cause illnesses to spread. Public transportation users have the potential to spread bacterial illnesses to others. To isolate, identify, and conduct an antibiotic sensitivity test on bacteria linked to public transportation vehicles and door handles, a bacteriological investigation of minibuses in Effurun was conducted. Eighty (80) samples in all were gathered from several Effurun parking lots. Salmonella species, Bacillus species, Escherichia coli, and Staphylococcus aureus were the bacteria that were isolated; S. aureus was the most common, occurring 40% of the time, while Bacillus species were the least common, occurring 10% of the time. The antibiotic with the highest sensitivity was Ciprofloxacin, whereas the one with the lowest sensitivity was Augmentin. However, it is assumed that as passengers use these door handles, the bacterial contamination changes. The organisms that are most likely to survive longer on these handles are those that can withstand a dry environment, such as the ones identified in our study. Frequent cleaning procedures could be an effective way to reduce the number of potentially harmful microorganisms that colonize.

Mapping of cholera Priority Areas for Multisectoral Interventions (PAMIs) using the 2023 GTFCC guidance: The Kenya experience

2025-06-20

Catherine Kiama , Emmanuel Okunga , Catherine Makwe +5 more | PLoS neglected tropical diseases

Cholera Priority Areas for Multisectoral Interventions (PAMIs), formerly known as “hotspots”, are limited geographical areas where cholera persists or regularly reappears due to cultural, environmental, and socioeconomic conditions. Focusing interventions … Cholera Priority Areas for Multisectoral Interventions (PAMIs), formerly known as “hotspots”, are limited geographical areas where cholera persists or regularly reappears due to cultural, environmental, and socioeconomic conditions. Focusing interventions on PAMIs will help to effectively control and ultimately eliminate cholera among the most at-risk populations. The 2023 GTFCC Methodology was used to identify PAMIs for cholera control in Kenya. The analysis was conducted between February and March 2024, selecting PAMIs based on the previous six years’ epidemiological data (Jan 2018 - Dec 2023) at the sub-county level. Epidemiological data was sourced from cholera outbreak line lists. The line list included both confirmed and suspected cholera cases of all ages admitted or reported to health facilities. The numerical priority index was calculated as a sum of four epidemiological indicators: incidence, mortality, persistence, and laboratory testing. Following a validation workshop, stakeholders selected a priority index threshold, identifying 78 sub-counties as initial PAMIs. There were 29 additional PAMIs included in the final list of 107 priority sub-counties based on country-specific vulnerability factors. This evidence-based approach will inform the targeting and implementation of multi-sectoral interventions in line with the Kenya National Cholera Plan.

Evaluation of bacteria pathogens with zoonotic potentials in catfish and pond water from selected fish farms, Ebonyi State, Nigeria

2025-06-20

S.C. Agwu , Celestine Azubuike Afiukwa , A. O. Oko +5 more | Journal of Aquatic Sciences

Fish, renowned for being a rich source of vital nutrients such as high-quality protein, polyunsaturated fatty acids, and essential minerals, can also act as a reservoir for zoonotic bacterial pathogens. … Fish, renowned for being a rich source of vital nutrients such as high-quality protein, polyunsaturated fatty acids, and essential minerals, can also act as a reservoir for zoonotic bacterial pathogens. These pathogens often indicate the level of environmental contamination in aquatic ecosystems. The study evaluated zoonotic bacterial pathogens in catfish and pond water samples from selected fish farms in Ebonyi State, Nigeria. A total of 72 samples, including catfish (48 samples) and pond water (24 samples), were collected from three locations: Abakaliki, Afikpo, and Ngbo. Standard microbiological and biochemical methods were employed to isolate, enumerate, and identify bacterial species. Morphological and biochemical analyses revealed the presence of Aeromonas sp., Vibrio sp., and Streptococcus sp. in both catfish and pond water samples. The biochemical analysis showed that Streptococcus sp. were positive to oxidase, lactase, glucose, sucrose, methyle red and catalase tests but showed negative result with Voges-Proskauer (VP) and citrate tests. However, Aeromonas species were positive to lactase, glucose, sucrose, methyl red, catalase, oxidase, indole and methyl red tests while Vibro species revealed to be variable to methyl red and VP-negative but positive to oxidase, lactase, glucose, sucrose, catalase and indole-negative, which were the same for both catfish and pond water samples. According to the distribution pattern of these microbes in the test samples, Aeromonas sp showed the highest prevalence (13.9%) in both test samples, while (18.75%) and (25%) were recorded in catfish and pond water respectively; their distribution across the three locations within the test samples were not statistically significant (p > 0.05), followed by Vibrio spp. (12.5%) in both samples while (18.75%) and (25%) were recorded in catfish and pond water respectively which their distribution were significant (p<0.05) and Streptococcus sp showed 8.3% in both samples while (12.5%) and (12.5%) were recorded in catfish and pond water respectively and the distribution pattern in the samples were not significant. The findings indicated compromised water quality in fish farms which is evident in the increased bacteria load, were likely influenced by environmental conditions and management practices.

Determination of Phylogroups, Pathotypes and Antibiotic Resistance Profiles of E. coli Isolates from Freshwater and Wastewater in the City of Panama

2025-06-20

Gonzalo Guevara , Emmanuel Michelangelli , Juan Raúl Medina-Sánchez +5 more | Pathogens

Untreated water bodies are critical ecological niches where environmental conditions can drive the adaptive evolution of bacterial populations, enabling them to acquire new traits such as antibiotic-resistance genes. Escherichia coli … Untreated water bodies are critical ecological niches where environmental conditions can drive the adaptive evolution of bacterial populations, enabling them to acquire new traits such as antibiotic-resistance genes. Escherichia coli is typically a commensal bacterium but can evolve into a pathogenic form, known as Diarrheagenic E. coli, responsible for both intestinal and extraintestinal diseases. This study focuses on the characterization of E. coli isolates from water samples collected from the Matasnillo River and the influence of the Juan Díaz Wastewater Treatment Plant (WWTP). While isolates from the Matasnillo River were classified as commensal, 18% of the isolates from the WWTP belonged to either phylogroups D or B2. Pathotype analysis revealed the presence of Entero-Toxigenic and Entero-Hemorrhagic E. coli in the WWTP. Moreover, Matasnillo River isolates exhibited resistance mainly to the quinolone ciprofloxacin, whereas those from the WWTP influent showed resistance to multiple broad-spectrum antibiotics. Sequencing analysis revealed the prevalence of the transmissible quinolone resistance qnrB19 among the Matasnillo River isolates and mutations conferring resistance to quinolone in gyrA, parC, and parE. These findings highlight the importance of monitoring antibiotic-resistant bacterial contamination in both freshwater and wastewater to mitigate the risk of the spread of resistant pathogens and potential epidemic outbreaks.

Vaccination against cholera in crisis: Coverage and cost efficiency in Sudan (2023–2024)

2025-06-19

Ahmad Izzoddeen , M.H. EL-Hussien , Omayma Abdalla +3 more | Vaccine

The emergence of ESBL and carbapenemase-producing Acinetobacter baumannii from cattle and environmental sources in Lagos, Nigeria

2025-06-19

| German Journal of Veterinary Research

Coliform Analysis and Molecular Characterization of E. coli in Krishna River Water near Vijayawada City

2025-06-19

G Chaitanya , Chinnam Bindu Kiranmayi , Tumati Srinivasa Rao +6 more | Deleted Journal

Large-scale genomic analysis reveals the distribution and diversity of type VI secretion systems in Escherichia coli

2025-06-18

Kristina Nešporová , Bart Steemans , Sander K. Govers | mSystems

ABSTRACT The type VI secretion system (T6SS) is a versatile nanomachine that injects effectors into target cells, playing a role in bacterial competition and virulence. While widespread in Gram-negative bacteria, … ABSTRACT The type VI secretion system (T6SS) is a versatile nanomachine that injects effectors into target cells, playing a role in bacterial competition and virulence. While widespread in Gram-negative bacteria, T6SS prevalence varies across species and strains, and its distribution in Escherichia coli remains underexplored despite it being an important intestinal (IPEC) and extraintestinal (ExPEC) pathogen. Here, we examined the prevalence of T6SS subclasses (T6SS i ) across 131,610 E. coli genomes, which we annotated for clinical relevance. T6SS genes were identified while focusing on the three subclasses present in E. coli: T6SS i1 , T6SS i2 , and T6SS i4b . Across phylogenetic groups, T6SS i1 was broadly present, while T6SS i2 showed associations with B1, B2, and G, and T6SS i4b was rare. T6SS i1 was primarily associated with IPEC, and T6SS i2 with ExPEC. Even clearer patterns emerged at the sequence type (ST) level. For example, both the most dominant ExPEC and IPEC ST (ST131 and ST11, respectively) displayed niche-specific trends, with non-complete T6SSs being more associated with humans. We also evaluated the co-occurrence of T6SSs with other virulence-associated genes (VAGs) and multidrug resistance (MDR). This analysis confirmed the association of T6SS i1 and T6SS i2 with IPEC- and ExPEC-associated VAGs, respectively, and revealed a negative correlation between complete T6SS i subclasses and MDR. Finally, we demonstrated how the presence of different T6SSs and VAGs can be used to examine and distinguish IPEC- and ExPEC-associated genomes. Together, our work provides a comprehensive overview of the diversity of T6SSs across E. coli , shedding more light on their potential contribution to pathogenicity in this species. IMPORTANCE Our study represents a large-scale analysis of T6SSs across one of the most comprehensive collections of E. coli genomes to date. In doing so, we updated several misconceptions on T6SSs distribution and other genomic properties of E. coli strains, which originated from smaller-scale studies and were subsequently extrapolated in the literature. This includes the prevalence and distribution of T6SS i subclasses across phylogenetic groups (e.g., T6SS i2 is not prevalent in phylogroup D), the association of specific virulence factors with IPEC and/or ExPEC (e.g., hemolysin A is more often associated with IPEC and not a typical ExPEC characteristic), and characteristics of pathogenic STs (e.g., ST131 displays distinct genomic properties based on its environmental niche). As such, this study not only advances our understanding of T6SS in E. coli but also serves as a valuable resource for future studies on the clinical relevance and distribution of other genetic elements.

Laboratory Analysis of the Resistance Spectrum and Antibacterial Susceptibility of Vibrio cholerae Strains Isolated in Kazakhstan from 1970 to 2024

2025-06-18

Zyat Abdel Z. , Zauresh Zhumadilova B. , Raikhan Mussagalieva S. +6 more | Research Square (Research Square)

<title>Abstract</title> <bold>C</bold>holera is an acute diarrheal disease caused by the bacterium <italic>Vibrio cholerae</italic>, transmitted via the fecal–oral route, primarily through contaminated water or food. Despite progress in vaccination and antibiotic … <title>Abstract</title> <bold>C</bold>holera is an acute diarrheal disease caused by the bacterium <italic>Vibrio cholerae</italic>, transmitted via the fecal–oral route, primarily through contaminated water or food. Despite progress in vaccination and antibiotic use, cholera continues to pose a significant public health threat, especially in regions with inadequate sanitation and unsafe drinking water. A major challenge in the management of cholera is the emergence of antibiotic-resistant <italic>V. cholerae</italic>strains, which compromise the effectiveness of standard therapeutic regimens. These resistant strains necessitate the development of novel treatment and prevention strategies. In 2018, studies on phenotypic resistance markers in <italic>Vibrio cholerae</italic>isolates collected in Kazakhstan revealed that 38.4% of the examined strains exhibited resistance, with monoresistant strains predominating (23.1%). Additionally, 9.6% of the isolates carried two or more resistance markers. Among the <italic>Vibrio cholerae</italic> O1 serogroup isolates, 38.5% were resistant, while in the non-O1 serogroup, resistance was observed in 40.0% of cases. <bold>Objectives: </bold>In this study, a comprehensive analysis was conducted on the antibiotic resistance of <italic>Vibrio cholerae</italic> strains isolated in Kazakhstan from 1970 to 2024, focusing on their susceptibility to various classes of antimicrobial agents. The molecular and biochemical mechanisms underlying the development of resistance were also investigated, and potential impacts on the epidemiological situation and biosafety were assessed. <bold>Methods</bold>: In this study, a total of 26 <italic>Vibrio cholerae</italic> strains isolated in Kazakhstan between 1970 and 2024 from clinical cases and environmental sources were used to screen for antimicrobial susceptibility and resistance profiles. Susceptibility testing was performed using the Kirby–Bauer disk diffusion method and E-test. To detect resistance genes, phenotypic assays and real-time Polymerase Chain Reaction were applied. One reference strain, 59 antibacterial agents across major drug classes, and a BacResista GLA Real-Time PCR Detection Kit were employed. <bold>Results</bold>: Phenotypic susceptibility testing of <italic>V. cholerae</italic> (n = 26) conducted in vitro demonstrated high sensitivity to cefotaxime, tetracycline, doxycycline, ciprofloxacin, and kanamycin. A similarly high level of susceptibility was observed for gentamicin, chloramphenicol, ampicillin, and rifampicin (96.2% of isolates). Real-time PCR results revealed no presence of resistance genes to glycopeptide or beta-lactam antibiotics in the tested <italic>V. cholerae</italic>strains. However, van A/B genes (Ct = 9.166, FAM channel) and the <bold>tem</bold>gene (Ct = 34.60, CY5 channel) were detected in the control strains <italic>Escherichia coli</italic> ATCC 25922 and <italic>Pseudomonas aeruginosa</italic> ATCC 9027 (Ct = 8.954 and 24.85, respectively). <bold>Conclusions</bold>: The absence of resistance to major classes of antimicrobial agents among all 26 <italic>V. cholerae</italic> isolates indicates the continued high clinical efficacy of these antibiotics in the treatment of cholera. These findings are of critical importance in the context of potential epidemic outbreaks, as they provide clinicians with a reliable basis for selecting empirical therapy.

Experimental evolution of a pathogen confronted with innate immune memory increases variation in virulence

2025-06-18

Ana Korša , Moritz Baur , Nora K. E. Schulz +3 more | PLoS Pathogens

Understanding the drivers and mechanisms of virulence evolution is still a major goal of evolutionary biologists and epidemiologists. Theory predicts that the way virulence evolves depends on the balance between … Understanding the drivers and mechanisms of virulence evolution is still a major goal of evolutionary biologists and epidemiologists. Theory predicts that the way virulence evolves depends on the balance between the benefits and costs it provides to pathogen fitness. Additionally, host responses to infections, such as resistance or tolerance, play a critical role in shaping virulence evolution. But, while the evolution of pathogens has been traditionally studied under the selection pressure of host adaptive immunity, less is known about their evolution when confronted to simpler and less effective forms of immunity such as immune priming. In this study, we used a well-established insect model for immune priming – red flour beetles and their bacterial pathogen Bacillus thuringiensis tenebrionis – to test how this form of innate immune memory drives the pathogen evolution. Through controlled experimental evolution of the pathogen in primed versus non-primed hosts, we found no change in average virulence after eight selection cycles in primed host. Nonetheless, we observed a notable rise in the variability of virulence, defined as the ability to kill hosts, among independent pathogen lines that evolved in primed hosts, and the bacteria were unable to develop resistance to host priming. Whole genome sequencing revealed increased activity in the bacterial mobilome (prophages and plasmids). Expression of the Cry toxin – a well-known virulence factor – was linked to evolved differences in copy number variation of the cry -carrying plasmid, though this did not correlate directly with virulence. These findings highlight that innate immune memory can drive variability in pathogen traits, which may favor adaptation to variable environments. This underscores the need to consider pathogen evolution in response to innate immune memory when applying these mechanisms in medicine, aquaculture, pest control, and insect mass production.

Post-traumatic wound infection after diving caused by Vibrio alginolyticus: a case report

2025-06-18

Julia Cebrián-López , Francisco Jover , Ana Infante-Urríos +2 more | Diving and Hyperbaric Medicine Journal

Vibrio alginolyticus is a facultatively anaerobic, Gram-negative bacillus that is a common component of marine flora. Infections caused by Vibrio alginolyticus are rare and typically occur following exposure to seawater … Vibrio alginolyticus is a facultatively anaerobic, Gram-negative bacillus that is a common component of marine flora. Infections caused by Vibrio alginolyticus are rare and typically occur following exposure to seawater or marine animals. This report details the clinical presentation and follow-up of a 65-year-old immunocompetent male who developed a wound infection due to Vibrio alginolyticus. Advanced diagnostic tools, such as MALDI-TOF mass spectrometry, can enhance the identification of these bacteria. Sport clinicians need to recognise Vibrio infections in seawater-contaminated wounds, as infections may be serious and the therapeutic approach may differ from conventional treatments.

Vibrio parahaemolyticus VtrB contributes to bile resistance and regulatory influences extend beyond the pathogenicity island (Vp-PAI)

2025-06-18

Lijun Yuan , Ruochun Gao , Laiwang Hou +2 more | Microbial Pathogenesis

Ficha de Malaveria neomaenas

2025-06-17

André Victor Lucci Freitas , Ana Maria Geraldes Rodrigues Pereira , Augusto Henrique Batista Rosa +7 more | Datasets - Sistema SALVE - ICMBio

Regulatory mechanism for host-cell contact-dependent T3SS gene expression in Vibrio parahaemolyticus

2025-06-17

Sarunporn Tandhavanant , Hiroyuki Terashima , Hirotaka Hiyoshi +6 more | mSystems

ABSTRACT Many pathogenic bacteria regulate gene expression in response to the surrounding environment to establish infection. One such mechanism is the regulation of gene expression in response to contact with … ABSTRACT Many pathogenic bacteria regulate gene expression in response to the surrounding environment to establish infection. One such mechanism is the regulation of gene expression in response to contact with host cells. Here, we show that Vibrio parahaemolyticus , a causative agent of foodborne gastroenteritis, has a host-cell contact-dependent regulatory mechanism for virulence gene expression. Type III secretion system 2 (T3SS2), an essential virulence determinant for acute gastroenteritis encoded by V. parahaemolyticus pathogenicity island (Vp-PAI), recognizes host-cell contact by sensing high intracellular K + levels and switching its secretory substrates. The switching of secretory substrates is regulated by proteins called gatekeepers. Mutants deficient in the gatekeeper genes lose the ability to switch secretory substrates and lock their secretory state into a host-cell contact-dependent manner. Transcriptomic analysis of these mutants revealed the upregulation of Vp-PAI genes, which was dependent on T3SS2 secretory activity, suggesting the presence of a negative regulator secreted by T3SS2. Comparative proteomic analyses identified a previously unrecognized T3SS2 secretory substrate, VPA1369 (VtrN), that negatively regulates Vp-PAI gene transcription. Secretion of VtrN was promoted under conditions that mimic host-cell contact. vtrN gene deletion specifically upregulated Vp-PAI gene expression, independent of T3SS2 secretory activity, indicating its role as a repressor. VtrN interacts with VtrB, a key transcription factor for Vp-PAI genes, suppressing its transcriptional activity. This mechanism illustrates how V. parahaemolyticus enhances virulence gene expression upon host-cell contact through the T3SS2 recognition system, highlighting an adaptive strategy for establishing infection. IMPORTANCE The type III secretion system (T3SS) is a crucial virulence factor tightly regulated for optimal host manipulation and virulence. This study revealed that the expression of T3SS2, a key virulence factor in Vibrio parahaemolyticus that causes acute gastroenteritis, is strictly regulated by host-cell contact. VtrN, a negative regulator exported from the bacterium through T3SS2, plays a key role in this host-cell contact-dependent gene transcriptional process. VtrN binds directly to the master regulator of Vp-PAI, the region encoding T3SS2, and represses its transcriptional activity. Upon host-cell contact, VtrN export is promoted, leading to the derepression of Vp-PAI gene expression. Thus, V. parahaemolyticus can effectively upregulate the expression of virulence factors when interacting with the host cells. Understanding these regulatory mechanisms could lead to innovative infection control strategies, opening new avenues for research and discovery.

Mathematical analysis and parameter estimation of the 2017–2018 cholera outbreak in Yemen

2025-06-16

Shaima Al-Shanfari , Ibrahim M. Elmojtaba , Nasser Al-Salti | The European Physical Journal Plus

Multiscale comparative pathogenomic analysis of Vibrio anguillarum linking serotype diversity, genomic plasticity and pathogenicity

2025-06-16

Khandker Shahed , Ashim Chakma , Omar Hamza Bin Manjur +1 more | Journal of Genetic Engineering and Biotechnology

Climate‑driven shifts in the growth and antimicrobial resistance of Vibrio cholerae, Morganella morganii, Aspergillus niger and Trichoderma harzianum

2025-06-16

Suadad Awad Kadhim , Saba Hussein Obeid | World Academy of Sciences Journal

Environmental Surveillance of Gram-Negative Bacteria and bla Genes in Hospital Facilities and Surrounding Waters in Thailand

2025-06-14

Sangrasami Meeprawat , Phuphiphat Jaikaew , Ruthada Chanklan +2 more | Journal of Current Science and Technology

To reveal the real time prevalent situation of antibiotic-resistant bacteria (ARB) and bla genes in Thailand, we monitored 83 isolates of Gram-negative bacteria (GNB) from hospital facilities and surrounding environmental … To reveal the real time prevalent situation of antibiotic-resistant bacteria (ARB) and bla genes in Thailand, we monitored 83 isolates of Gram-negative bacteria (GNB) from hospital facilities and surrounding environmental waters. 16S rRNA gene sequencing was performed. Polymerase chain reactions were employed for bla gene detection. Disk diffusion was used for antimicrobial susceptibility testing. As a result, Enterobacter mori (20%) and Klebsiella pneumoniae (17.14%) were prevalent in hospital facilities, while K. pneumoniae (27.08%) and Enterobacter cloacae (14.58%) prevailed in water samples. Ampicillin resistance rates were highest, at 65.71% and 66.67% in hospital and water isolates, respectively. Enterobacter species from water samples exhibited multidrug-resistant characteristics. blaSHV and blaTEM were highly prevalent, 91.43% and 89.58% in various bacterial species from hospital facilities and water samples, respectively. The coexistence of blaSHV and blaTEM and blaNDM was the most common overall (16.87%). The prevalence of the same bacterial species and bla genes in both sectors suggests the cross-transfer of ARGs and resistant bacteria between different environments, hospital and water. The findings emphasize concerns about the safety of water sources and bacterial contamination in hospital facilities.

Aging and climate change-induced heat stress synergistically increase susceptibility to Vibrio vulnificus infection via an altered gut microbiome-immune axis

2025-06-13

Subhajit Roy , Madhura More , Ayushi Trivedi +6 more | The Science of The Total Environment

Climate change is exacerbating heatwaves, significantly increasing public health risks, including heightened vulnerability to Vibrio vulnificus infections, especially among older adults. While heat stress alone impairs immune regulation and compromises … Climate change is exacerbating heatwaves, significantly increasing public health risks, including heightened vulnerability to Vibrio vulnificus infections, especially among older adults. While heat stress alone impairs immune regulation and compromises gut integrity, the combined effects of aging and climate-induced heat stress on infectious severity remain insufficiently explored. Using young (12-week-old) and aged (24-month-old) mouse models, we examined how aging and periodic heat stress synergistically influence susceptibility to Vibrio vulnificus by assessing gut microbiome alterations, immune responses, and antibiotic resistance gene dynamics. Heat stress markedly impaired intestinal barrier function, induced significant microbiome shifts, elevated systemic inflammation, and promoted enrichment of antibiotic resistance genes particularly those conferring tetracycline resistance with effects significantly amplified in aged mice. Upon Vibrio vulnificus infection, aged heat-stressed mice demonstrated elevated inflammatory responses, severe intestinal damage, and pronounced immune dysregulation compared to younger counterparts. Gut depletion and probiotic recolonization models further validated microbiota involvement, showing that Roseburia intestinalis significantly reduced heat stress-exacerbated CD4+ T-cell immunosenescence in aged mice. Collectively, this study provides robust experimental evidence highlighting the critical interplay between aging and climate-driven heat stress in intensifying infectious disease severity via microbiome-immune axis disruptions, underscoring the need for microbiota-targeted strategies in climate-vulnerable populations.

Comprehensive genomic analysis of type VI secretion system diversity and associated proteins in Serratia

2025-06-13

Lili Jiang , Wenjing Yi , Yang Zhao +7 more | Microbial Genomics

The type VI secretion system (T6SS) is a contact-dependent contractile nanomachine widely distributed among Gram-negative bacteria, essential for interbacterial competition, host interactions and environmental adaptation. The T6SS encoded by Serratia … The type VI secretion system (T6SS) is a contact-dependent contractile nanomachine widely distributed among Gram-negative bacteria, essential for interbacterial competition, host interactions and environmental adaptation. The T6SS encoded by Serratia is known to play roles in bacterial competition and contribute to niche adaptation. Yet, the diversity and distribution of T6SS loci and relevant proteins across different Serratia species remain underexplored. In this study, we conducted bioinformatic and comparative genomic analyses of the T6SS to expand our understanding of T6SS in Serratia and their distribution within the genus. A dataset comprising 2,337 Serratia genomes was analysed, identifying 4 distinct T6SS loci classified into 3 main types based on TssB sequence variation, with varying distributions across specific Serratia haplogroups. T6SS serratia-1b subtype was found to be the most prevalent. By integrating homology searches and positional information, we expanded the known database of T6SS proteins in Serratia , identifying a range of effectors likely involved in interbacterial interactions and host adaptation. Additionally, statistical analysis reveals a strong correlation between the presence of T6SS and the diversity of associated genes, including not only known T6SS effectors and immunity proteins but also other co-occurring gene families, enabling the identification of multiple candidate loci potentially involved in bacterial competition and pathogenicity. These findings shed light on the complex distribution, evolutionary dynamics and functional diversity of T6SS and associated proteins in Serratia , advancing our understanding of their role in bacterial competition and environmental adaptation.

Deciphering the Salmonella T6SS toolkit: two decades of research decoding a versatile bacterial weapon

2025-06-13

Carlos J. Blondel , Fernando A. Amaya , Felipe Reyes-Méndez +7 more | Journal of Bacteriology

ABSTRACT The Type VI Secretion System (T6SS) is a critical fitness and virulence factor of many Gram-negative bacteria. Five T6SS gene clusters have been described in Salmonella , each one … ABSTRACT The Type VI Secretion System (T6SS) is a critical fitness and virulence factor of many Gram-negative bacteria. Five T6SS gene clusters have been described in Salmonella , each one encoded within different pathogenicity islands (i.e., SPI-6, SPI-19, SPI-20, SPI-21, and SPI-22). The events of gain and loss of these T6SS gene clusters have contributed to shape the genome evolution of different Salmonella serotypes. In addition, the differential distribution of T6SS and the ever-increasing repertoire of predicted effector proteins is likely to play an important role in the environmental fitness and pathogenic potential of different Salmonella serotypes. This review summarizes the current knowledge on the role played by T6SS in Salmonella biology, highlighting the major milestones in the field over the past two decades. We discuss the expanding repertoire of T6SS effector proteins identified to date and examine the current understanding of mechanisms controlling T6SS expression in Salmonella , focusing on host-derived cues and regulators involved. Finally, we provide a critical analysis of conflicting reports and suggest future directions for the research in the field. A better understanding of these processes could expand our knowledge of Salmonella biology, and the mechanisms behind how this versatile secretion system enables Salmonella to thrive in competitive microbial environments and contribute to host colonization.

The Competitive Edge: T6SS-Mediated Interference Competition by Vibrionaceae Across Marine Ecological Niches

2025-06-12

Perla Jazmin Gonzalez Moreno , Michele K. Nishiguchi | Microorganisms

Interference competition, wherein bacteria actively antagonize and damage their microbial neighbors, is a key ecological strategy governing microbial community structure and composition. To gain a competitive edge, bacteria can deploy … Interference competition, wherein bacteria actively antagonize and damage their microbial neighbors, is a key ecological strategy governing microbial community structure and composition. To gain a competitive edge, bacteria can deploy a diverse array of antimicrobial weapons—ranging from diffusible toxins to contact-mediated systems in order to eliminate their bacterial rivals. Among Gram-negative bacteria, the type VI secretion system (T6SS) has emerged as a potent and sophisticated contact-dependent mechanism that enables the delivery of toxic cargo into neighboring cells, thereby promoting the colonization and dominance of a bacterial taxon within an ecological niche. In this review, we examine the ecological significance of T6SS-mediated interference competition by members of the Vibrionaceae family across a range of marine habitats that include free-living microbial communities and host-associated niches such as coral and squid symbioses. Additionally, we explore the ecological impact of T6SS-mediated competition in modulating biofilm community structure and promoting horizontal gene transfer within those complex microbial populations. Together, these insights underscore the ecological versatility of the T6SS and emphasize its role in driving antagonistic bacterial interactions and shaping microbial community dynamics within marine ecosystems.

Bacteria poison and eat their neighbors

2025-06-12

Carey D. Nadell , Christopher J. Marx | Science

Bacteria leverage a secretion system to kill and scavenge nutrients from nearby competitors. Bacteria leverage a secretion system to kill and scavenge nutrients from nearby competitors.

Antagonism as a foraging strategy in microbial communities

2025-06-12

Astrid KM Stubbusch , François J. Peaudecerf , Kang Soo Lee +7 more | Science

In natural habitats, nutrient availability limits bacterial growth. We discovered that bacteria can overcome this limitation by acquiring nutrients by lysing neighboring cells through contact-dependent antagonism. Using single-cell live imaging … In natural habitats, nutrient availability limits bacterial growth. We discovered that bacteria can overcome this limitation by acquiring nutrients by lysing neighboring cells through contact-dependent antagonism. Using single-cell live imaging and isotopic markers, we found that during starvation, the type VI secretion system (T6SS) lysed neighboring cells and thus provided nutrients from lysing cells for growth. Genomic adaptations in antagonists, characterized by a reduced metabolic gene repertoire, and the previously unexplored distribution of the T6SS across bacterial taxa in natural environments suggest that bacterial antagonism may contribute to nutrient transfer within microbial communities in many ecosystems.

Long-term Analysis of Vibrio vulnificus and Vibrio parahaemolyticus Virulence Factors and Their Environmental Associations in the Chesapeake Bay, Maryland, U.S.

2025-06-12

Michele E. Morgado , Kyle D. Brumfield , Suhana Chattopadhyay +4 more | Journal of Applied Microbiology

Abstract Aims The present study analyzed long-term trends in Vibrio spp. virulence factors associated with pathogenicity in Chesapeake Bay waters (in Maryland) across two three-year sampling periods (2009-2012 and 2019-2022). … Abstract Aims The present study analyzed long-term trends in Vibrio spp. virulence factors associated with pathogenicity in Chesapeake Bay waters (in Maryland) across two three-year sampling periods (2009-2012 and 2019-2022). Methods and Results V. parahaemolyticus (n=1,476) and V. vulnificus (n=806) isolates were recovered from 13 sampling stations and tested for species-specific and virulence markers. Across both sampling periods, detection of V. parahaemolyticus tdh+/trh+ isolates was similar and more frequently observed in the spring and fall, and the upper sampling stations. However, significant differences were observed in the detection of V. vulnificus pilA+ and rtxA+ isolates, with a higher percentage of pilA+ in 2019-2022 and rtxA+ in 2009-2012. VcgC+ isolates were most frequently detected during the fall (n=24%) in 2019-2022. Interestingly, a greater prevalence of V. vulnificus isolates harboring virulence markers was observed in the mid and lower stations. Conclusions V. vulnificus isolates displayed greater changes in virulence marker frequency across sampling periods compared to V. parahaemolyticus and these markers were detectable throughout the year.

Integrons: the hidden architects of bacterial adaptation, evolution, and the challenges of antimicrobial resistance

2025-06-12

Harjeet Singh , Shivani Pandya , Srushti Jasani +5 more | Antonie van Leeuwenhoek