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Journal of Bacteriology Aug 2018is a potent opportunistic human pathogen that contaminates the human food chain by asymptomatically colonizing seafood. The expression of the 9-gene exopolysaccharide...
is a potent opportunistic human pathogen that contaminates the human food chain by asymptomatically colonizing seafood. The expression of the 9-gene exopolysaccharide locus mediates surface adherence and is controlled by the secondary signaling molecule c-di-GMP and the regulator BrpT. Here, we show that c-di-GMP and BrpT also regulate the expression of an adjacent 5-gene cluster that includes the operon, , and another VpsT-like transcriptional regulator gene, The expression of the 14 genes spanning the region increased with elevated intracellular c-di-GMP levels in a BrpT-dependent manner, save for , which was positively regulated by c-di-GMP and repressed by BrpT. BrpS repressed expression and was required for rugose colony development. The mutation of its consensus WFSA c-di-GMP binding motif blocked these activities, suggesting that BrpS function is dependent on binding c-di-GMP. BrpT specifically bound the , , and promoters, and binding sites homologous to the VpsT binding site were identified upstream of and Transcription was initiated distal to , and a conserved RfaH-recruiting element and a potential Rho utilization () terminator site were identified within the 100-bp leader region, suggesting the integration of early termination and operon polarity suppression into the regulation of transcription. The GC content and codon usage of the 16-kb region was 5.5% lower relative to that of the flanking DNA, suggesting its recent assimilation via horizontal transfer. Thus, architecturally, the region can be considered an acquired biofilm and rugosity island that is subject to complex regulation. Biofilm and rugose colony formation are developmental programs that underpin the evolution of as a potent opportunistic human pathogen and successful environmental organism. A better understanding of the regulatory pathways governing theses phenotypes promotes the development and implementation of strategies to mitigate food chain contamination by this pathogen. c-di-GMP signaling is central to both pathways. We show that the molecule orchestrates the expression of 14 genes clustered in a 16-kb segment of the genome that governs biofilm and rugose colony development. This region exhibits the hallmarks of horizontal transfer, suggesting complex regulatory control of a recently assimilated genetic island governing the colonization response of .
Topics: Bacterial Proteins; Biofilms; Gene Expression Regulation, Bacterial; Gene Transfer, Horizontal; Genome, Bacterial; Genomic Islands; Operon; Phenotype; Promoter Regions, Genetic; Signal Transduction; Vibrio vulnificus
PubMed: 29760209
DOI: 10.1128/JB.00190-18 -
Biocontrol Science 2022Vibrio vulnificus, an opportunistic human pathogen responsible for primary septicemia, initiates pathogenesis by attachment to the intestinal epithelial cells for which...
Vibrio vulnificus, an opportunistic human pathogen responsible for primary septicemia, initiates pathogenesis by attachment to the intestinal epithelial cells for which the motility by the polar flagellum plays an essential role. The proteomic analysis of outer membrane proteins showed that the treatment with the 1/2 minimum inhibitory concentration (MIC) of polymyxin B (a bacterial antimicrobial peptide) led to the reduced production of flagellin (a major component of the polar flagellum). Furthermore, the bacterial motility was inhibited in the presence of 1/2 MIC of polymyxin B. V. vulnificus has six flagellin genes organized into the flaFBA and flaCDE loci. The flaA was found to be expressed higher than flaC, and its expression was significantly decreased by polymyxin B. As well as polymyxin B, the 1/2 MIC of LL-37 (a human intestinal antimicrobial peptide) reduced the expression of flaA. In addition, among four fragments of LL-37, KI-18 and FK-13 containing FKRIVQRIKDELR could lead to the decreased expression of flaA. Because the motility closely relates to virulence of V. vulnificus, the findings obtained herein indicate that LL-37 may reduce the bacterial virulence through inhibition of the motility via the polar flagellum.
Topics: Flagella; Flagellin; Humans; Polymyxin B; Proteomics; Vibrio vulnificus
PubMed: 35753794
DOI: 10.4265/bio.27.57 -
Pathogens and Disease Nov 2015The ability for bacteria to attach to and detach from various substrata is important for colonization, survival and transitioning to new environments. An opportunistic...
The ability for bacteria to attach to and detach from various substrata is important for colonization, survival and transitioning to new environments. An opportunistic human pathogen, Vibrio vulnificus, can cause potentially fatal septicemia after ingestion of undercooked seafood. Based on genetic polymorphisms, strains of this species are subtyped into clinical (C) and environmental (E) genotypes. Vibrio vulnificus readily associates with chitin, thus we investigated chitin detachment dynamics in these disparate genotypes. We found that C-genotypes detach significantly more than E-genotypes after 24 hours in aerobic as well as anaerobic conditions. Furthermore, expression of genes involved in type IV pilin production was significantly downregulated in C-genotypes compared to E-genotypes, suggesting an importance in detachment. Interestingly, gbpA, a gene that has been shown to be important in host colonization in V. cholerae, was upregulated in the C-genotypes during detachment. Additionally, we found that C-genotypes detached to a greater extent, and produced more quorum-sensing (QS) autoinducer-2 molecules relative to E-genotypes, which suggests a role for QS in detachment. These findings suggest that for V. vulnificus, QS-mediated detachment may be a potential mechanism for transitioning into a human host for C-genotypes, while facilitating E-genotype maintenance in the estuarine environment.
Topics: Aerobiosis; Anaerobiosis; Bacterial Adhesion; Chitin; Fimbriae Proteins; Gene Expression Profiling; Genetic Variation; Genotype; Homoserine; Humans; Lactones; Quorum Sensing; Vibrio Infections; Vibrio vulnificus; Water Microbiology
PubMed: 26377182
DOI: 10.1093/femspd/ftv072 -
PloS One 2015Vibrio vulnificus is a common gram-negative bacterium, which might cause morbidity and mortality in patients following consumption of seafood or exposure to seawater in... (Clinical Trial)
Clinical Trial
Vibrio vulnificus is a common gram-negative bacterium, which might cause morbidity and mortality in patients following consumption of seafood or exposure to seawater in Southeast China. We retrospectively analyzed clinical data of patients with laboratory confirmed V. vulnificus infection. Twenty one patients were divided into a survival group and a non-surviving (or death) group according to their clinical outcome. Clinical data and measurements were statistically analyzed. Four patients (19.05%) died and five patients gave positive cultures from bile fluid, and 16 other patients gave positive culture from blood or blisters. Ten patients (47.62%) had an underlying liver disease and marine-related events were found in sixteen patients (76.2%). Patients with heavy drinking habits might be at increased mortality (p = 0.028). Clinical manifestations of cellulitis (47.6%), septic shock (42.9%) and multiple organ failure (28.6%) were statistically significant when comparing survivors and non-survivors (p = 0.035, p = 0.021 and p = 0.003, respectively). The laboratory results, including hemoglobin < 9.0 g/L (p = 0.012), platelets < 2.0 × 109 /L, prothrombin time activity (PTA) <20%, decreased serum creatinine and increased urea nitrogen were statistically significant (p = 0.012, p = 0.003, p = 0.028 and p = 0.028, respectively). Patients may be at a higher risk of mortality under situations where they have a history of habitual heavy alcoholic drink consumption (p = 0.028, OR = 22.5, 95%CI 1.5-335.3), accompanied with cellulitis, shock, multiple organ failure, and laboratory examinations that are complicated by decreased platelets, hemoglobin and significantly prolonged prothrombin time (PT).
Topics: Adult; Aged; Disease-Free Survival; Female; Humans; Male; Middle Aged; Risk Factors; Survival Rate; Vibrio Infections; Vibrio vulnificus
PubMed: 26274504
DOI: 10.1371/journal.pone.0136019 -
The Journal of Infectious Diseases Feb 2019The bacterial pathogen Vibrio vulnificus causes severe septic foodborne infections. The multifunctional autoprocessing repeats-in-toxins (MARTX) toxin is an important...
BACKGROUND
The bacterial pathogen Vibrio vulnificus causes severe septic foodborne infections. The multifunctional autoprocessing repeats-in-toxins (MARTX) toxin is an important secreted virulence factor. The effector domain region is essential for lethal intestinal infection in mice, but the contribution of each of the 5 effector domains to infection has not been investigated.
METHODS
V. vulnificus mutants with varying effector domain content were inoculated intragastrically to mice, and the time to death was monitored to establish the contribution of each effector domain to overall virulence. Each strain was also tested for bacterial dissemination from the intestine to internal organs and for inhibition of phagocytosis.
RESULTS
The effector domain region was required for V. vulnificus to inhibit phagocytosis by J774 macrophages, but no single effector domain was required. No single MARTX effector domain was necessary for bacterial dissemination. Nonetheless, overall survival of infected mice differed with respect to the infecting V. vulnificus strain. Removal of rid or rrsp significantly reduced the virulence potential of V. vulnificus, while deletion of duf1 or abh accelerated the time to death.
CONCLUSION
Rho GTPases inactivation domain and Ras/Rap1-specific endopeptidase each exert greater effects on virulence than other MARTX domains, suggesting that modulation of the Rho/Ras family of GTPases is a critical function of the toxin during intestinal infection.
Topics: Animals; Bacterial Toxins; Endopeptidases; Female; Mice, Inbred ICR; Phagocytosis; Protein Domains; Substrate Specificity; Vibrio Infections; Vibrio vulnificus; Virulence; Virulence Factors; rap1 GTP-Binding Proteins; ras Proteins; rho GTP-Binding Proteins
PubMed: 30289477
DOI: 10.1093/infdis/jiy590 -
PloS One 2013Vibrio vulnificus is a ubiquitous marine bacterium that is responsible for infections and some seafood-related illnesses and deaths in the United States, mainly in...
Vibrio vulnificus is a ubiquitous marine bacterium that is responsible for infections and some seafood-related illnesses and deaths in the United States, mainly in individuals with compromised health status in the Gulf of Mexico region. Most phylogenetic studies focus on V. vulnificus strains isolated in the southern United States, but almost no genetic data are available on northeastern bacterial isolates of clinical or environmental origin. Our goal in this study was to examine the genetic diversity of environmental strains isolated from commercially-produced oysters and in clinical strains of known pathogenicity in northeastern United States. We conducted analyses of a total of eighty-three strains of V. vulnificus, including 18 clinical strains known to be pathogenic. A polyphasic, molecular-typing approach was carried out, based upon established biotypes, vcg, CPS, 16S rRNA types and three other genes possibly associated with virulence (arylsulfatase A, mtlABC, and nanA). An established Multi Locus Sequence Typing (MLST) method was also performed. Phylogenetic analyses of these markers and MLST results produced similar patterns of clustering of strains into two main lineages (we categorized as 'LI' and 'LII'), with clinical and environmental strains clustering together in both lineages. Lineage LII was comprised primarily but not entirely of clinical bacterial isolates. Putative virulence markers were present in both clinical and environmental strains. These results suggest that some northeastern environmental strains of V. vulnificus are phylogenetically close to clinical strains and probably are capable of virulence. Further studies are necessary to assess the risk of human illness from consuming raw oysters harvested in the northeastern US.
Topics: Environmental Microbiology; Food Microbiology; Genetic Variation; Humans; Molecular Sequence Data; Molecular Typing; Multilocus Sequence Typing; Phylogeny; Polymorphism, Genetic; Seafood; Vibrio Infections; Vibrio vulnificus
PubMed: 24386187
DOI: 10.1371/journal.pone.0083357 -
BMC Genomics Mar 2021Tilapia (Oreochromis niloticus) cultures are frequently infected by Vibrio vulnificus, causing major economic losses to production units. Previously, tilapia expressing...
Comparative transcriptome analysis reveals ectopic delta-5 and delta-6 desaturases enhance protective gene expression upon Vibrio vulnificus challenge in Tilapia (Oreochromis niloticus).
BACKGROUND
Tilapia (Oreochromis niloticus) cultures are frequently infected by Vibrio vulnificus, causing major economic losses to production units. Previously, tilapia expressing recombinant delta-5 desaturase and delta-6 desaturase (D56) were found to be resistant to V. vulnificus infection. In this report, we profile the D56-mediated molecular changes underlying this resistance in tilapia. A comparative transcriptome analysis was performed on V. vulnificus-infected wild-type and D56-transgenic tilapia using Illumina's sequencing-by-synthesis approach. Gene enrichment analysis on differentially expressed unigenes was performed, and the expression patterns were validated by real-time PCR.
RESULTS
Comparative transcriptome analysis was performed on RNA-sequence profiles obtained from wild-type and D56-transgenic tilapia at 0, 6 and 24 h post-infection with V. vulnificaus. GO and KEGG gene enrichment analyses showed that D56 regulates several pathways and genes, including fatty acid (FA) metabolism associated, and inflammatory and immune response. Expression of selected FA metabolism-associated, inflammatory and immune responsive genes was validated by qPCR. The inflammatory and immune responsive genes that are modulated by FA-associated D56 likely contribute to the enhanced resistance against V. vulnificus infection in Tilapia.
CONCLUSIONS
Transcriptome profiling and filtering for two-fold change variation showed that 3795 genes were upregulated and 1839 genes were downregulated in D56-transgenic tilapia. These genes were grouped into pathways, such as FA metabolism, FA elongation, FA biosynthesis, biosynthesis of unsaturated FA, FA degradation, inflammation, immune response, and chemokines. FA-associated genes and immune-related genes were modulated by D56 at 6 h and 24 h post infection with V. vulnificus. The expression patterns of FA-related genes, inflammatory genes, antimicrobial peptide genes and immune responsive genes at 0, 3, 6, 12, 24 and 48 h post-infection suggests these genes are involved in the enhanced resistance of D56 transgenic tilapia to V. vulnificus.
Topics: Animals; Cichlids; Fish Diseases; Gene Expression Profiling; Tilapia; Transcriptome; Vibrio Infections; Vibrio vulnificus
PubMed: 33752587
DOI: 10.1186/s12864-021-07521-5 -
PloS One 2015The genetic diversity and population structure of Vibrio vulnificus isolates from Korea and Taiwan were investigated using PCR-based assays targeting putative...
The genetic diversity and population structure of Vibrio vulnificus isolates from Korea and Taiwan were investigated using PCR-based assays targeting putative virulence-related genes and multilocus sequence typing (MLST). BOX-PCR genomic fingerprinting identified 52 unique genotypes in 84 environmental and clinical V. vulnificus isolates. The majority (> 50%) of strains had pathogenic genotypes for all loci tested; moreover, many environmental strains had pathogenic genotypes. Although significant (p < 0.05) inter-relationships among the genotypes were observed, the association between genotype and strain source (environmental or clinical) was not significant, indicating that genotypic characteristics alone are not sufficient to predict the isolation source or the virulence of a given V. vulnificus strain and vice versa. MLST revealed 23-35 allelic types per locus analyzed, resulting in a total of 44 unique sequence types (STs). Two major monophyletic groups (lineages A and B) corresponding to the two known lineages of V. vulnificus were observed; lineage A had six STs that were exclusively environmental, whereas lineage B had STs from both environmental and clinical sources. Pathogenic and nonpathogenic genotypes predominated in MLST lineages B and A, respectively. In addition, V. vulnificus was shown to be in linkage disequilibrium (p < 0.05), although two different recombination tests (PHI and Sawyer's tests) detected significant evidence of recombination. Tajima's D test also indicated that V. vulnificus might be comprised of recently sub-divided lineages. These results suggested that the two lineages revealed by MLST correspond to two distinct ecotypes of V. vulnificus.
Topics: DNA Fingerprinting; Genetic Variation; Genetics, Population; Humans; Korea; Linkage Disequilibrium; Multilocus Sequence Typing; Phylogeny; RNA, Ribosomal; Republic of Korea; Seafood; Sequence Analysis, DNA; Taiwan; Vibrio Infections; Vibrio vulnificus
PubMed: 26599487
DOI: 10.1371/journal.pone.0142657 -
Biological & Pharmaceutical Bulletin 2022Vibrio vulnificus is a Gram-negative estuarine bacterium that causes infection in immuno-compromised patients, eels, and shrimp. V. vulnificus NCIMB2137, a...
Vibrio vulnificus is a Gram-negative estuarine bacterium that causes infection in immuno-compromised patients, eels, and shrimp. V. vulnificus NCIMB2137, a metalloprotease-negative strain isolated from a diseased eel, produces a 45-kDa chymotrypsin-like alkaline serine protease known as VvsA. The gene encoding vvsA also includes another gene, vvsB with an unknown function; however, it is assumed to be an essential molecular chaperone for the maturation of VvsA. In the present study, we used an in vitro cell-free translation system to examine the maturation pathway of VvsA. We individually expressed the vvsA and vvsB genes and detected their mRNAs. However, the sample produced from vvsA did not exhibit protease activity. A sodium dodecyl sulfate (SDS) analysis detected the VvsB protein, but not the VvsA protein. A Western blotting analysis using a histidine (His)-tag at the amino terminus of proteins also showed no protein production by vvsA. These results suggested the translation, but not the transcription of vvsA. Factors derived from Escherichia coli were used in the in vitro cell-free translation system employed in the present study. The operon of the serine protease gene containing vvsA and vvsB was expressed in E. coli. Although serine proteases were produced, they were cleaved at different sites and no active mature forms were detected. These results indicate that the operon encoding vvsA and vvsB is a gene constructed to be specifically expressed in V. vulnificus.
Topics: Humans; Vibrio vulnificus; Serine Proteases; Escherichia coli; Serine Endopeptidases
PubMed: 36328494
DOI: 10.1248/bpb.b22-00106 -
The Journal of Veterinary Medical... Jul 2015Vibrio vulnificus is the causative agent of primary septicemia, wound infection and gastroenteritis in immunocompromised people. In this study, signature-tagged...
Vibrio vulnificus is the causative agent of primary septicemia, wound infection and gastroenteritis in immunocompromised people. In this study, signature-tagged mutagenesis (STM) was applied to identify the virulence genes of V. vulnificus. Using STM, 6,480 mutants in total were constructed and divided into 81 sets (INPUT pools); each mutant in a set was assigned a different tag. Each INPUT pool was intraperitoneally injected into iron-overloaded mice, and in vivo surviving mutants were collected from blood samples from the heart (OUTPUT pools). From the genomic DNA of mixed INPUT or OUTPUT pools, digoxigenin-labeled DNA probes against the tagged region were prepared and used for dot hybridization. Thirty tentatively attenuated mutants, which were hybridized clearly with INPUT probes but barely with OUTPUT probes, were negatively selected. Lethal doses of 11 of the 30 mutants were reduced to more than 1/100; of these, the lethal doses of 2 were reduced to as low as 1/100,000. Transposon-inserted genes in the 11 attenuated mutants were those for IMP dehydrogenase, UDP-N-acetylglucosamine-2-epimerase, aspartokinase, phosphoribosylformylglycinamidine cyclo-ligase, malate Na (+) symporter and hypothetical protein. When mice were immunized with an attenuated mutant strain into which IMP dehydrogenase had been inserted with a transposon, they were protected against V. vulnificus infection. In this study, we demonstrated that the STM method can be used to search for the virulence genes of V. vulnificus.
Topics: Animals; DNA Probes; Female; Genes, Bacterial; Mice; Mice, Inbred ICR; Mutagenesis, Insertional; Vibrio vulnificus; Virulence Factors
PubMed: 25755021
DOI: 10.1292/jvms.14-0655