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MicrobiologyOpen Oct 2023Rifampicin resistance, which is genetically linked to mutations in the RNA polymerase β-subunit gene rpoB, has a global impact on bacterial transcription and cell...
Rifampicin resistance, which is genetically linked to mutations in the RNA polymerase β-subunit gene rpoB, has a global impact on bacterial transcription and cell physiology. Previously, we identified a substitution of serine 522 in RpoB (i.e., RpoB ) conferring rifampicin resistance to Vibrio vulnificus, a human food-borne and wound-infecting pathogen associated with a high mortality rate. Transcriptional and physiological analysis of V. vulnificus expressing RpoB showed increased basal transcription of stress-related genes and global virulence regulators. Phenotypically these transcriptional changes manifest as disturbed osmo-stress responses and toxin-associated hypervirulence as shown by reduced hypoosmotic-stress resistance and enhanced cytotoxicity of the RpoB strain. These results suggest that RpoB-linked rifampicin resistance has a significant impact on V. vulnificus survival in the environment and during infection.
Topics: Humans; Rifampin; Vibrio vulnificus; Bacterial Proteins; Mutation; Virulence; DNA-Directed RNA Polymerases
PubMed: 37877661
DOI: 10.1002/mbo3.1379 -
Trends in Microbiology Dec 2022The fulminating zoonotic pathogen Vibrio vulnificus is the causative agent of fatal septicemia in humans and fish, raising tremendous economic burdens in healthcare and... (Review)
Review
The fulminating zoonotic pathogen Vibrio vulnificus is the causative agent of fatal septicemia in humans and fish, raising tremendous economic burdens in healthcare and the aquaculture industry. V. vulnificus exploits various virulence factors, including biofilm-related factors and exotoxins, for its persistence in nature and pathogenesis during infection. Substantial studies have found that the expression of virulence factors is coordinately regulated by numerous transcription factors that recognize the changing environments. Here, we summarize and discuss the recent discoveries of the physiological roles of virulence factors in V. vulnificus and their regulation by transcription factors in response to various environmental signals. This expanded understanding of molecular pathogenesis would provide novel clues to develop an effective antivirulence therapy against V. vulnificus infection.
Topics: Animals; Humans; Vibrio vulnificus; Virulence Factors; Virulence; Transcription Factors; Biofilms
PubMed: 35753865
DOI: 10.1016/j.tim.2022.05.009 -
Microorganisms Oct 2023() and () are water- and foodborne bacteria that can cause several distinct human diseases, collectively called vibriosis. The success of oyster aquaculture is... (Review)
Review
() and () are water- and foodborne bacteria that can cause several distinct human diseases, collectively called vibriosis. The success of oyster aquaculture is negatively impacted by high abundances. Myriad environmental factors affect the distribution of pathogenic , including temperature, salinity, eutrophication, extreme weather events, and plankton loads, including harmful algal blooms. In this paper, we synthesize the current understanding of ecological drivers of and and provide a summary of various tools used to enumerate and in a variety of environments and environmental samples. We also highlight the limitations and benefits of each of the measurement tools and propose example alternative tools for more specific enumeration of pathogenic and . Improvement of molecular methods can tighten better predictive models that are potentially important for mitigation in more controlled environments such as aquaculture.
PubMed: 37894160
DOI: 10.3390/microorganisms11102502 -
BMC Microbiology Mar 2020Vibrio vulnificus hemolysin (VVH) is a pore-forming toxin secreted by Vibrio vulnificus. Cellular cholesterol was believed to be the receptor for VVH, because...
BACKGROUND
Vibrio vulnificus hemolysin (VVH) is a pore-forming toxin secreted by Vibrio vulnificus. Cellular cholesterol was believed to be the receptor for VVH, because cholesterol could bind to VVH and preincubation with cholesterol inhibited cytotoxicity. It has been reported that specific glycans such as N-acetyl-D-galactosamine and N-acetyl-D-lactosamine bind to VVH, however, it has not been known whether these glycans could inhibit the cytotoxicity of VVH without oligomer formation. Thus, to date, binding mechanisms of VVH to cellular membrane, including specific receptors have not been elucidated.
RESULTS
We show here that VVH associates with ganglioside GM1a, Fucosyl-GM1, GD1a, GT1c, and GD1b by glycan array. Among them, GM1a could pulldown VVH. Moreover, the GD1a inhibited the cytotoxicity of VVH without the formation of oligomers.
CONCLUSION
This is the first report of a molecule able to inhibit the binding of VVH to target cells without oligomerization of VVH.
Topics: Animals; Bacterial Proteins; Binding Sites; CHO Cells; Cell Membrane; Cholesterol; Cricetulus; Gangliosides; Glycomics; Hemolysin Proteins; Microarray Analysis; Protein Binding; Protein Conformation; Protein Multimerization; Vibrio vulnificus
PubMed: 32228455
DOI: 10.1186/s12866-020-01755-1 -
Microorganisms Apr 2024Bacteria in the genus are ubiquitous in estuarine and coastal waters. Some species (including and are known human pathogens causing ailments like cholera, diarrhea,...
Bacteria in the genus are ubiquitous in estuarine and coastal waters. Some species (including and are known human pathogens causing ailments like cholera, diarrhea, or septicemia. Notably, can also cause a severe systemic infection (known as vibriosis) in eels raised in aquaculture facilities. Water samples were periodically collected from the estuary of the Asahi River, located in the southern part of Okayama City, Japan. These samples were directly plated onto CHROMagar Vibrio plates, and colonies displaying turquoise-blue coloration were selected. Thereafter, polymerase chain reaction was used to identify and . A total of 30 strains and 194 strains were isolated during the warm season when the water temperature (WT) was higher than 20 °C. Concurrently, an increase in coliforms was observed during this period. Notably, has two genotypes, designated as genotype 1 and genotype 2. Genotype 1 is pathogenic to humans, while genotype 2 is pathogenic to both humans and eels. The loop-mediated isothermal amplification method was developed to rapidly determine genotypes at a low cost. Of the 194 strains isolated, 80 (41.2%) were identified as genotype 1 strains. Among the 41 strains isolated when the WTs were higher than 28 °C, 25 strains (61.0%) belonged to genotype 1. In contrast, of the 32 strains isolated when the WTs were lower than 24 °C, 27 strains (84.4%) belonged to genotype 2. These results suggest that the distribution of the two genotypes was influenced by WT.
PubMed: 38792707
DOI: 10.3390/microorganisms12050877 -
Biomedical and Environmental Sciences :... Feb 2023This study investigated how the natural phytophenol and potent SIRT1 activator resveratrol (RSV) regulate necroptosis during induced sepsis and the potential mechanism.
OBJECTIVE
This study investigated how the natural phytophenol and potent SIRT1 activator resveratrol (RSV) regulate necroptosis during induced sepsis and the potential mechanism.
METHODS
The effect of RSV on cytolysin (VVC)-induced necroptosis was analyzed using CCK-8 and Western blot assays. Enzyme-linked immunosorbent assays and quantitative real-time polymerase chain reaction, western blot, and immunohistochemistry and survival analyses were performed to elucidate the effect and mechanism of RSV on necroptosis in a -induced sepsis mouse model.
RESULTS
RSV relieved necroptosis induced by VVC in RAW264.7 and MLE12 cells. RSV also inhibited the inflammatory response, had a protective effect on histopathological changes, and reduced the expression level of the necroptosis indicator pMLKL in peritoneal macrophages, lung, spleen, and liver tissues of -induced septic mice . Pretreatment with RSV downregulated the mRNA of the necroptosis indicator and protein expression in peritoneal macrophages and tissues of -induced septic mice. RSV also improved the survival of -induced septic mice.
CONCLUSION
Our findings collectively demonstrate that RSV prevented -induced sepsis by attenuating necroptosis, highlighting its potency in the clinical management of -induced sepsis.
Topics: Animals; Mice; Necroptosis; Resveratrol; Vibrio vulnificus; Sepsis; Blotting, Western
PubMed: 36861192
DOI: 10.3967/bes2023.017 -
BMC Microbiology Aug 2022Vibrio vulnificus is a pathogenic bacterium that causes disease in marine fish, affecting fish farming and human health worldwide. In May 2021, in the Bohai Bay region,...
Vibrio vulnificus is a pathogenic bacterium that causes disease in marine fish, affecting fish farming and human health worldwide. In May 2021, in the Bohai Bay region, a disease broke out in commercially farmed pearl gentian grouper (♀Epinephelus fuscoguttatus × ♂Epinephelus lanceolatus), causing huge economic losses. The diseased fish had skin lesions, water accumulation in their abdomens, and showed tissue and organ damage. V. vulnificus biotype 2 has been reported in eels and other marine fish, but it is less reported in pearl gentian grouper. In this study, the pathogenic strain isolated from diseased fish was identified as V. vulnificus EPL 0201 biotype 2 on the basis of physiological and biochemical characteristics and the results of 16S rRNA gene and gyrB sequencing, virulence gene detection, and recursive infection experiments. To gain a comprehensive understanding of the pathogenicity and drug resistance of this strain, whole-genome sequencing was performed. Whole-genome analysis showed that the gene map of this strain was complete. The Virulence Factor Database annotation results showed that this strain had the key virulence factor genes vvhA and rtxA, which cause host disease. In addition, this strain had genes conferring resistance against cephalosporins, aminoglycosides, tetracyclines, and sulfonamides. Antimicrobial susceptibility testing confirmed the presence of these resistance genes identified in the genome. The results of this study show that V. vulnificus EPL 0201 biotype 2 is a multi-drug resistant strain with high pathogenicity.
Topics: Animals; Anti-Bacterial Agents; Bass; Eels; Humans; RNA, Ribosomal, 16S; Vibrio; Vibrio Infections; Vibrio vulnificus; Virulence Factors
PubMed: 35974308
DOI: 10.1186/s12866-022-02610-1 -
Applied and Environmental Microbiology Feb 2018and are naturally occurring estuarine bacteria and are the leading causes of seafood-associated infections and mortality in the United States. Though...
and are naturally occurring estuarine bacteria and are the leading causes of seafood-associated infections and mortality in the United States. Though multiple-antibiotic-resistant and strains have been reported, resistance patterns in vibrios are not as well documented as those of other foodborne bacterial pathogens. Salinity relaying (SR) is a postharvest processing (PHP) treatment to reduce the abundances of these pathogens in shellfish harvested during the warmer months. The purpose of this study was to evaluate the antimicrobial susceptibility (AMS), pathogenicity, and genetic profiles of and recovered from oysters during an oyster relay study. Isolates ( [ = 296] and [ = 94]) were recovered from oysters before and during the 21-day relaying study to detect virulence genes ( and ) and genes correlated with virulence () using multiplex quantitative PCR (qPCR). AMS to 20 different antibiotics was investigated using microbroth dilution, and pulsed-field gel electrophoresis (PFGE) was used to study the genetic profiles of the isolates. Twenty percent of isolates were , while 1 and 2% of were and , respectively. More than 77% of the isolates and 30% of the isolates were resistant to at least one antimicrobial. Forty-eight percent of and 8% of isolates were resistant to two or more antimicrobials. All isolates demonstrated a high genetic diversity, even among those isolated from the same site and having a similar AMS profile. No significant effects of the relaying process on AMS, virulence genes, or PFGE profiles of and were observed. Analysis of the antibiotic resistance profiles of and isolated from oysters during this study indicated that more than 48% of isolates were resistant to two or more antimicrobials, including those recommended by the CDC for treating infections. Also, the isolates showed high MICs for some of the infection treatment antibiotics. Monitoring of AMS profiles of this bacterium is important to ensure optimal treatment of infections and improve food safety. Our study showed no significant differences in the AMS profiles of ( = 0.26) and ( = 0.23) isolated from the oysters collected before versus after relaying. This suggests that the salinity of the relaying sites did not affect the AMS profiles of the isolates, although it did reduce the numbers of these bacteria in oysters (S. Parveen et al., J Food Sci 82:484-491, 2017, https://doi.org/10.1111/1750-3841.13584).
Topics: Animals; Anti-Bacterial Agents; Bacterial Proteins; Colony Count, Microbial; Drug Resistance, Multiple, Bacterial; Food Handling; Food Safety; Genetic Variation; Microbial Sensitivity Tests; Ostreidae; Polymerase Chain Reaction; Salinity; Shellfish; Vibrio Infections; Vibrio parahaemolyticus; Vibrio vulnificus; Virulence
PubMed: 29150510
DOI: 10.1128/AEM.01790-17 -
Frontiers in Cellular and Infection... 2021RtxA1 is a major cytotoxin of () causing fatal septicemia and necrotic wound infections. Our previous work has shown that RpoS regulates the expression and secretion of...
RtxA1 is a major cytotoxin of () causing fatal septicemia and necrotic wound infections. Our previous work has shown that RpoS regulates the expression and secretion of RtxA1 toxin. This study was conducted to further investigate the potential mechanisms of RpoS on RtxA1 secretion. First, TolCV1 and TolCV2 proteins, two TolC homologs, were measured at various time points by Western blotting. The expression of TolCV1 was increased time-dependently, whereas that of TolCV2 was decreased. Expression of both TolCV1 and TolCV2 was significantly downregulated in an deletion mutation. Subsequently, we explored the roles of TolCV1 and TolCV2 in pathogenesis. Western blot analysis showed that RtxA1 toxin was exported by TolCV1, not TolCV2, which was consistent with the cytotoxicity results. Furthermore, the expression of TolCV1 and TolCV2 was increased after treatment of the host signal bile salt and the growth of mutant was totally abolished in the presence of bile salt. A mutation resulted in significant reduction of induced-virulence in mice. Taken together, TolCV1 plays key roles in RtxA1 secretion, bile salt resistance, and mice lethality of , suggesting that TolCV1 could be an attractive target for the design of new medicines to treat infections.
Topics: Animals; Bacterial Proteins; Escherichia coli; Mice; Vibrio Infections; Vibrio vulnificus; Virulence
PubMed: 33996641
DOI: 10.3389/fcimb.2021.673222 -
Molecular and Cellular Probes Jun 2021Vibrio vulnificus (V. vulnificus) is a Gram-negative bacterium living in warm and salty water. This marine bacterium could produce hemolysin (VVH), which often causes...
Vibrio vulnificus (V. vulnificus) is a Gram-negative bacterium living in warm and salty water. This marine bacterium could produce hemolysin (VVH), which often causes serious gastroenteritis or septicemia when people contact to seawater or seafood containing V. vulnificus. Timely diagnosis is regard as essential to disease surveillance. In this paper, we aimed at developing a quick and sensitive method for the detection of Vibrio vulnificus using real time recombinase polymerase amplification (real time RPA). Specific primers and an exo probe were designed on the basis of the vvhA gene sequence available in GenBank. Target DNA could be amplified and labeled with specific fluorophore within 20 min at 38 °C. The method exhibited a high specificity, only detecting Vibrio vulnificus and not showing cross-reaction with other bacteria. The sensitivity of this method was 2 pg per reaction (20 μL) for DNA, or 200 copies per reaction (20 μL) for standard plasmid. The detection limit (LOD) stated as the target level that would be detected 95% of the time and estimated was 1.58 × 10 copies by fit of the probit to the results of 8 replicates in different concentration. For quantitative analysis of the real time RPA, the second order polynomial regression was adopted in our study. The results showed the correlation coefficients were raised above 0.98, which suggested this model might be a better choice for the quantitative analysis of real time RPA compared to the routine linear regression model. For artificially contaminated plasma samples, Vibrio vulnificus could be detected within 16 min by real time RPA at concentration as low as 1.2 × 10 CFU/mL or 2.4 CFU per reaction (20 μL). Thus, the real time RPA method established in this study shows great potential for detecting Vibrio vulnificus in the research laboratory and disease diagnosis.
Topics: DNA Primers; Humans; Polymerase Chain Reaction; Recombinases; Sensitivity and Specificity; Vibrio vulnificus
PubMed: 33789126
DOI: 10.1016/j.mcp.2021.101726