Genetic Distinctions among Clinical and Environmental Strains of Vibrio vulnificus

ABSTRACT Vibrio vulnificus causes rare but frequently fatal septicemia associated with raw oyster consumption by persons with underlying hepatic or immune system dysfunction. The virulence potential of environmental reservoirs appears widely distributed, because most strains are virulent in animal models; however, several investigations recently demonstrated genetic divergence among strains from clinical versus environmental origin at independent genetic loci. The present study used PCR to screen DNA polymorphisms in strains from environmental (n = 35) or clinical (n = 33) sources, and genomic relationships were determined by repetitive extragenic palindromic DNA PCR (rep-PCR) typing. Significant (P < 0.01) association was observed for typical “clinical” or “environmental” polymorphism profiles based on strain origin. Most oyster isolates (88%), including all of those with the “environmental” profile, also formed a single rep-PCR genogroup. Clinical isolates within this group did not have the typical “clinical” profile. On the other hand, clinical isolates with the typical polymorphism profile were distributed among multiple rep-PCR genogroups, demonstrating greater genetic diversity than was evident by profiling genetic polymorphisms. Wound isolates were genetically distinct from typical blood isolates by all assays. Strains from an outbreak of wound infections in Israel (biotype 3) were closely related to several U.S. strains by rep-PCR, indicating potential reservoirs of emerging disease. Strains genetically related to blood isolates appeared to be relatively rare in oysters, as only one had the “clinical” polymorphism profile or clustered by rep-PCR. However, this study was not an extensive survey, and more sampling using rep-PCR for sensitive genetic discrimination is needed to determine the virulence potential of environmental reservoirs.

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TolCV1 Has Multifaceted Roles During Vibrio vulnificus Infection

Frontiers in Cellular and Infection Microbiology ◽

10.3389/fcimb.2021.673222 ◽

2021 ◽

Vol 11 ◽

Author(s):

Yue Gong ◽

Rui Hong Guo ◽

Joon Haeng Rhee ◽

Young Ran Kim

Keyword(s):

Escherichia Coli ◽

Western Blot ◽

Bile Salt ◽

Vibrio Vulnificus ◽

Salt Resistance ◽

Wound Infections ◽

Time Points ◽

Host Signal ◽

Fatal Septicemia ◽

Vulnificus Infection

RtxA1 is a major cytotoxin of Vibrio vulnificus (V. vulnificus) causing fatal septicemia and necrotic wound infections. Our previous work has shown that RpoS regulates the expression and secretion of V. vulnificus RtxA1 toxin. This study was conducted to further investigate the potential mechanisms of RpoS on RtxA1 secretion. First, V. vulnificus TolCV1 and TolCV2 proteins, two Escherichia coli 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 rpoS deletion mutation. Subsequently, we explored the roles of TolCV1 and TolCV2 in V. vulnificus 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 tolCV1 mutant was totally abolished in the presence of bile salt. A tolCV1 mutation resulted in significant reduction of V. vulnificus induced-virulence in mice. Taken together, TolCV1 plays key roles in RtxA1 secretion, bile salt resistance, and mice lethality of V. vulnificus, suggesting that TolCV1 could be an attractive target for the design of new medicines to treat V. vulnificus infections.

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Biochemical and Virulence Characterization of Vibrio vulnificus Isolates From Clinical and Environmental Sources

Frontiers in Cellular and Infection Microbiology ◽

10.3389/fcimb.2021.637019 ◽

2021 ◽

Vol 11 ◽

Author(s):

Keri A. Lydon ◽

Thomas Kinsey ◽

Chinh Le ◽

Paul A. Gulig ◽

Jessica L. Jones

Keyword(s):

Mouse Model ◽

Vibrio Vulnificus ◽

Human Infection ◽

Clinical Isolates ◽

Rrna Gene ◽

Mixed Genotype ◽

Strain Isolation ◽

Virulence Potential ◽

Individual Mouse ◽

Biochemical Profiles

Vibrio vulnificus is a deadly human pathogen for which infections occur via seafood consumption (foodborne) or direct contact with wounds. Virulence is not fully characterized for this organism; however, there is evidence of biochemical and genotypic correlations with virulence potential. In this study, biochemical profiles and virulence genotype, based on 16S rRNA gene (rrn) and virulence correlated gene (vcg) types, were determined for 30 clinical and 39 oyster isolates. Oyster isolates were more biochemically diverse than the clinical isolates, with four of the 20 tests producing variable (defined as 20–80% of isolates) results. Whereas, for clinical isolates only mannitol fermentation, which has previously been associated with virulence potential, varied among the isolates. Nearly half (43%) of clinical isolates were the more virulent genotype (rrnB/vcgC); this trend was consistent when only looking at clinical isolates from blood. The majority (64%) of oyster isolates were the less virulent genotype (rrnA or AB/vcgE). These data were used to select a sub-set of 27 isolates for virulence testing with a subcutaneously inoculated, iron-dextran treated mouse model. Based on the mouse model data, 11 isolates were non-lethal, whereas 16 isolates were lethal, indicating a potential for human infection. Within the non-lethal group there were eight oyster and three clinical isolates. Six of the non-lethal isolates were the less virulent genotype (rrnA/vcgE or rrnAB/vcgE) and two were rrnB/vcgC with the remaining two of mixed genotype (rrnAB/vcgC and rrnB/vcgE). Of the lethal isolates, five were oysters and 11 were clinical. Eight of the lethal isolates were the less virulent genotype and seven the more virulent genotype, with the remaining isolate a mixed genotype (rrnA/vcgC). A discordance between virulence genotype and individual mouse virulence parameters (liver infection, skin infection, skin lesion score, and body temperature) was observed; the variable most strongly associated with mouse virulence parameters was season (warm or cold conditions at time of strain isolation), with more virulent strains isolated from cold conditions. These results indicate that biochemical profiles and genotype are not significantly associated with virulence potential, as determined by a mouse model. However, a relationship with virulence potential and seasonality was observed.

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Carbapenem-Resistant Klebsiella pneumoniae Clinical Isolates: In Vivo Virulence Assessment in Galleria mellonella and Potential Therapeutics by Polycationic Oligoethyleneimine

Antibiotics ◽

10.3390/antibiotics10010056 ◽

2021 ◽

Vol 10 (1) ◽

pp. 56

Author(s):

Dalila Mil-Homens ◽

Maria Martins ◽

José Barbosa ◽

Gabriel Serafim ◽

Maria J. Sarmento ◽

...

Keyword(s):

Klebsiella Pneumoniae ◽

Galleria Mellonella ◽

Multidrug Resistant ◽

In Vitro Models ◽

Clinical Isolates ◽

In Vivo Model ◽

Virulence Potential ◽

Hospital Acquired

Klebsiella pneumoniae, one of the most common pathogens found in hospital-acquired infections, is often resistant to multiple antibiotics. In fact, multidrug-resistant (MDR) K. pneumoniae producing KPC or OXA-48-like carbapenemases are recognized as a serious global health threat. In this sense, we evaluated the virulence of K. pneumoniae KPC(+) or OXA-48(+) aiming at potential antimicrobial therapeutics. K. pneumoniae carbapenemase (KPC) and the expanded-spectrum oxacillinase OXA-48 isolates were obtained from patients treated in medical care units in Lisbon, Portugal. The virulence potential of the K. pneumonia clinical isolates was tested using the Galleria mellonella model. For that, G. mellonella larvae were inoculated using patients KPC(+) and OXA-48(+) isolates. Using this in vivo model, the KPC(+) K. pneumoniae isolates showed to be, on average, more virulent than OXA-48(+). Virulence was found attenuated when a low bacterial inoculum (one magnitude lower) was tested. In addition, we also report the use of a synthetic polycationic oligomer (L-OEI-h) as a potential antimicrobial agent to fight infectious diseases caused by MDR bacteria. L-OEI-h has a broad-spectrum antibacterial activity and exerts a significantly bactericidal activity within the first 5-30 min treatment, causing lysis of the cytoplasmic membrane. Importantly, the polycationic oligomer showed low toxicity against in vitro models and no visible cytotoxicity (measured by survival and health index) was noted on the in vivo model (G. mellonella), thus L-OEI-h is foreseen as a promising polymer therapeutic for the treatment of MDR K. pneumoniae infections.

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Hemochromatosis and Vibrio vulnificus Wound Infections

Journal of Clinical Gastroenterology ◽

10.1097/mcg.0b013e31819069c1 ◽

2009 ◽

Vol 43 (9) ◽

pp. 890-893 ◽

Cited By ~ 39

Author(s):

James C. Barton ◽

Ronald T. Acton

Keyword(s):

Vibrio Vulnificus ◽

Wound Infections

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Seasonality, clinical types and prognostic factors of Vibrio vulnificus infection

The Journal of Infection in Developing Countries ◽

10.3855/jidc.3008 ◽

2013 ◽

Vol 7 (07) ◽

pp. 533-540 ◽

Cited By ~ 11

Author(s):

Chien-Han Tsao ◽

Chun-Chieh Chen ◽

Shih-Jei Tsai ◽

Chi-Rong Li ◽

Wai-Nang Chao ◽

...

Keyword(s):

Necrotizing Fasciitis ◽

Case Fatality Rate ◽

Vibrio Vulnificus ◽

Case Fatality ◽

Skin Lesions ◽

Wound Infections ◽

Fatality Rate ◽

Group 2 ◽

Vulnificus Infection ◽

Group 1

Introduction: Vibrio vulnificus infection, an uncommon but life-threatening illness, manifests as two main types, primary septicemia and primary wound infections. Little information regarding the seasonality of V. vulnificus infections in tropical areas and prognostic factors of primary V. vulnificus wound infections is available. Methodology: This retrospective study was conducted to include 159 V. vulnificus-infected admissions at our institution in southern Taiwan, 63 with primary septicemia (Group 1) and 96 with primary wound infections (Group 2), from 1999 to 2008, for analysis. Results: The case-fatality rate was 24%. Eighty-eight percent of these cases occurred during April to November. During December to March, patients in Group 2 were less likely to have acquired the infection compared with those in Group 1. Group 1 was more likely to have comorbidities and a higher case-fatality rate compared to Group 2. In multivariate analysis, hemorrhagic bullous skin lesions/necrotizing fasciitis (P=0.024), lesions involving two or more limbs (P=0.043), and shock on admission (P=0.015) were related to an increased mortality risk, while surgery < 24 hours after admission (P=0.001) was related to a decreased mortality risk in Group 1; however, hemorrhagic bullous skin lesions/necrotizing fasciitis (P=0.045) was the only prognostic factor in Group 2. Conclusion: The presence of hemorrhagic bullous lesion/necrotizing fasciitis is the main prognostic factor for primary septicemia or primary wound infections caused by V. vulnificus. Persons with an underlying immunocompromised status should avoid consuming raw/undercooked seafood or exposing wounds to seawater and should wear clothing during handling of seafood/fishing, especially in warmer months.

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Molecular and Physical Factors That Influence Attachment of Vibrio vulnificus to Chitin

Applied and Environmental Microbiology ◽

10.1128/aem.00753-15 ◽

2015 ◽

Vol 81 (18) ◽

pp. 6158-6165 ◽

Cited By ~ 13

Author(s):

Tiffany C. Williams ◽

Mesrop Ayrapetyan ◽

James D. Oliver

Keyword(s):

Quorum Sensing ◽

Vibrio Vulnificus ◽

The United States ◽

Type Iv Pili ◽

Negative Regulator ◽

Physical Factors ◽

Wound Infections ◽

Environmental Persistence ◽

Content Type ◽

Type Iv

ABSTRACTThe human pathogenVibrio vulnificusis the leading cause of seafood-related deaths in the United States. Strains are genotyped on the basis of alleles that correlate with isolation source, with clinical (C)-genotype strains being more often implicated in disease and environmental (E)-genotype strains being more frequently isolated from oysters and estuarine waters. Previously, we have shown that the ecologically distinct C- and E-genotype strains ofV. vulnificusdisplay different degrees of chitin attachment, with C-genotype strains exhibiting reduced attachment relative to their E-genotype strain counterparts. We identified type IV pili to be part of the molecular basis for this observed genotypic variance, as E-genotype strains exhibit higher levels of expression of these genes than C-genotype strains. Here, we used a C-genotype quorum-sensing (QS) mutant to demonstrate that quorum sensing is a negative regulator of type IV pilus expression, which results in decreased chitin attachment. Furthermore, calcium depletion reduced E-genotype strain attachment to chitin, which suggests that calcium is necessary for proper functioning of the type IV pili in E-genotype strains. We also found that starvation or dormancy can alter the efficiency of chitin attachment, which has significant implications for the environmental persistence ofV. vulnificus. With the increasing incidence of wound infections caused byV. vulnificus, we investigated a subset of E-genotype strains isolated from human wound infections and discovered that they attached to chitin in a manner more similar to that of C-genotype strains. This study enhances our understanding of the molecular and physical factors that mediate chitin attachment inV. vulnificus, providing insight into the mechanisms that facilitate the persistence of this pathogen in its native environment.

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Phenotypical and molecular assessment of the virulence potential of KPC-3-producing Klebsiella pneumoniae ST392 clinical isolates

Microbiological Research ◽

10.1016/j.micres.2020.126551 ◽

2020 ◽

Vol 240 ◽

pp. 126551

Author(s):

Danilo D’Apolito ◽

Fabio Arena ◽

Viola Conte ◽

Lucia Henrici De Angelis ◽

Giuseppina Di Mento ◽

...

Keyword(s):

Klebsiella Pneumoniae ◽

Clinical Isolates ◽

Virulence Potential ◽

Molecular Assessment

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Evaluation of Genotypic and Phenotypic Methods To Distinguish Clinical from Environmental Vibrio vulnificus Strains

Applied and Environmental Microbiology ◽

10.1128/aem.01594-08 ◽

2009 ◽

Vol 75 (6) ◽

pp. 1604-1613 ◽

Cited By ~ 39

Author(s):

Eva Sanjuán ◽

Belén Fouz ◽

James D. Oliver ◽

Carmen Amaro

Keyword(s):

16S Rrna ◽

Vibrio Vulnificus ◽

Large Strain ◽

Bacterial Species ◽

Dna Polymorphisms ◽

Biolog System ◽

Strain Collection ◽

Phenotypic Methods ◽

Type Ab

ABSTRACT Vibrio vulnificus is a heterogeneous bacterial species that comprises virulent and avirulent strains from environmental and clinical sources that have been grouped into three biotypes. To validate the typing methods proposed to distinguish clinical from environmental isolates, we performed phenotypic (API 20E, API 20NE, and BIOLOG tests) and genetic (ribotyping and DNA polymorphism at several loci) studies with a large strain collection representing different biotypes, origins, and host ranges. No phenotypic method was useful for biotyping or grouping strains with regard to the origin of an isolate, and only the BIOLOG system was reliable for identifying the strains at the species level. DNA polymorphisms divided the population into three major profiles. Profile 1 strains were vcg type C, 16S rRNA type B, and vvh type 1 and included most of the biotype 1 human septicemic isolates; profile 2 strains were vcg type E, 16S rRNA type A, and vvh type 2 and included all biotype 2 isolates together with biotype 1 isolates from fish and water and some human isolates; and profile 3 strains were vcg type E, 16S rRNA type AB, and vvh type 2 and included biotype 3 strains. Ribotyping divided the species into two groups: one group that included profile 1 biotype 1 isolates and one group that included isolates of all three biotypes with the three profiles described above. In conclusion, no genotyping system was able to distinguish either clinical strains from environmental strains or biogroups within the species V. vulnificus, which suggests that new typing methodologies useful for public health have to be developed for this species.

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