Halophilic, lactose-positive Vibrio in a case of fatal septicemia

Vibrio parahaemolyticus Infection in Mice Reduces Protective Gut Microbiota, Augmenting Disease Pathways

Vibrio parahaemolyticus (Vp), a major food-borne pathogen, is responsible for severe infections such as gastroenteritis and septicemia, which may be accompanied by life-threatening complications. While studies have evaluated factors that affect the virulence of the pathogen, none have investigated the interaction of Vp with gut microbiota. To address this knowledge gap, we compared the effect of Vp on gut bacterial community structure, immunity, liver and kidney function, in pseudo germ-free (PGF) mice and normal (control) mice. Significant damage to the ileum was observed in normal mice compared with the PGF mice. The inflammatory factors IL-1β, IL-6, and TNF-α in normal mice were ∼2.5-fold higher than in the PGF mice, and liver (ALT, AST, ALP) and kidney (BUN) function indices were ∼1.6-fold higher. The Vp infection substantially reduced species composition and richness of the gut microbial communities. In particular, there was a shift in keystone taxa, from protective species of genera Bacteroides, Lactobacillus, Bifidobacterium, and Akkermansia in the gut of control mice to opportunistic pathogens Enterobacteriaceae, Proteus, Prevotella, and Sutterella in Vp-infected mice, thus affecting microbiota-related biological functions in the mice. Specifically, pathways involved in infectious diseases and ion channels were significantly augmented in infected mice, while the pathways involved in metabolism, digestion and cell growth declined. We propose that the normal mice are more prone to Vp infection because of the alteration in gut-microbe-mediated functions. All these effects reduce intestinal resistance, with marked damage to the gut lining and pathogen leakage into the blood culminating in liver and kidney damage. These findings greatly advance our understanding of the mechanisms underlying interactions between Vp, the gut microbiota and the infected host.

Climate influence on Vibrio and associated human diseases during the past half-century in the coastal North Atlantic

Climate change is having a dramatic impact on marine animal and plant communities but little is known of its influence on marine prokaryotes, which represent the largest living biomass in the world oceans and play a fundamental role in maintaining life on our planet. In this study, for the first time to our knowledge, experimental evidence is provided on the link between multidecadal climatic variability in the temperate North Atlantic and the presence and spread of an important group of marine prokaryotes, the vibrios, which are responsible for several infections in both humans and animals. Using archived formalin-preserved plankton samples collected by the Continuous Plankton Recorder survey over the past half-century (1958-2011), we assessed retrospectively the relative abundance of vibrios, including human pathogens, in nine areas of the North Atlantic and North Sea and showed correlation with climate and plankton changes. Generalized additive models revealed that long-term increase in Vibrio abundance is promoted by increasing sea surface temperatures (up to ∼1.5 °C over the past 54 y) and is positively correlated with the Northern Hemisphere Temperature (NHT) and Atlantic Multidecadal Oscillation (AMO) climatic indices (P < 0.001). Such increases are associated with an unprecedented occurrence of environmentally acquired Vibrio infections in the human population of Northern Europe and the Atlantic coast of the United States in recent years.

Temporal and spatial distribution patterns of potentially pathogenic Vibrio spp. at recreational beaches of the German north sea

The number of reported Vibrio-related wound infections associated with recreational bathing in Northern Europe has increased within the last decades. In order to study the health risk from potentially pathogenic Vibrio spp. in the central Wadden Sea, the seasonal and spatial distribution of Vibrio vulnificus, Vibrio parahaemolyticus, Vibrio alginolyticus and Vibrio cholerae were investigated at ten recreational beaches in this area over a 2-year period. V. alginolyticus and V. parahaemolyticus were found to be omnipresent all year round in the study area, while V. vulnificus occurrence was restricted to summer months in the estuaries of the rivers Ems and Weser. Multiple linear regression models revealed that water temperature is the most important determinant of Vibrio spp. occurrence in the area. Differentiated regression models showed a species-specific response to water temperature and revealed a particularly strong effect of even minor temperature increases on the probability of detecting V. vulnificus in summer. In sediments, Vibrio spp. concentrations were up to three orders of magnitude higher than in water. Also, V. alginolyticus and V. parahaemolyticus were found to be less susceptible towards winter temperatures in the benthic environment than in the water, indicating an important role of sediments for Vibrio ecology. While only a very small percentage of tested V. parahaemolyticus proved to be potentially pathogenic, the presence of V. vulnificus during the summer months should be regarded with care.

Vibrio parahaemolyticus ExsE is requisite for initial adhesion and subsequent type III secretion system 1-dependent autophagy in HeLa cells

Vibrio parahaemolyticus pandemic serotype O3 : K6 causes acute gastroenteritis, wound infections and septicaemia in humans. This organism encodes two type III secretion systems (T3SS1 and T3SS2); host-cell cytotoxicity has been attributed to T3SS1. Synthesis and secretion of T3SS1 proteins is positively regulated by ExsA, which is presumptively regulated by the ExsCDE pathway, similar to Pseudomonas aeruginosa. Herein we deleted the putative exsE from V. parahaemolyticus and found constitutive expression of the T3SS1 in broth culture as expected. More importantly, however, in a cell culture model, the ΔexsE strain was unable to induce cytotoxicity, as measured by release of lactate dehydrogenase (LDH), or autophagy, as measured by LC3 conversion. This is markedly different from P. aeruginosa, where deletion of exsE has no effect on host-cell cytolysis. Swarming and cytoadhesion were reduced for the deletion mutant and could be recovered along with T3SS1-induced HeLa cell cytotoxicity by in cis expression of exsE in the ΔexsE strain. Loss of adhesion and swarming motility was associated with the loss of flagella biogenesis in the exsE-deficient strain. Mouse mortality was unaffected by the deletion of exsE compared with a wild-type control, suggesting that additional adhesins are important for intoxication in vivo. Based on these data, we conclude that ExsE contributes to the negative regulation of T3SS1 and, in addition, contributes to regulation of an adherence phenotype that is requisite for translocation of effector proteins into HeLa cells.

Transcription of Vibrio parahaemolyticus T3SS1 genes is regulated by a dual regulation system consisting of the ExsACDE regulatory cascade and H-NS

Vibrio parahaemolyticus, one of the human pathogenic vibrios, causes gastroenteritis, wound infections and septicemia. Genomic sequencing of this organism revealed that it has two distinct type III secretion systems (T3SS1 and T3SS2). T3SS1 plays a significant role in lethal activity in a murine infection model. It was reported that expression of the T3SS1 gene is controlled by a positive regulator, ExsA, and a negative regulator, ExsD, which share a degree of sequence similarity with Pseudomonas aeruginosa ExsA and ExsD, respectively. However, it is unknown whether T3SS1 is regulated by a mechanism similar to that demonstrated for P. aeruginosa, because functional analysis of VP1701, which is homologous to ExsC, is lacking and there is no ExsE homologue in the T3SS1 region. Here, we demonstrate that vp1701 and vp1702 are functional orthologues of exsC and exsE, respectively, of P. aeruginosa. VP1701 was required for the production of T3SS1-related proteins. VP1702 was a negative regulator for T3SS1-related protein production and was secreted by T3SS1. We also found that H-NS represses T3SS1-related gene expression by suppressing exsA gene expression. These findings indicate that the transcription of V. parahaemolyticus T3SS1 genes is regulated by a dual regulatory system consisting of the ExsACDE regulatory cascade and H-NS.

Environmental occurrence and clinical impact of Vibrio vulnificus and Vibrio parahaemolyticus: a European perspective

Vibrio vulnificus and Vibrio parahaemolyticus are ubiquitous Gram-negative bacterial pathogens found naturally in marine and estuarine waters, and are a leading cause of seafood-associated bacterial illness. These pathogens are commonly reported in the USA and in many Asian countries, including China, Japan and Taiwan; however, there is growing concern that V. vulnificus and V. parahaemolyticus may represent an important and increasing clinical problem in Europe. Several factors underlie the need for a greater understanding of these non-cholera vibrios within a European context. First, there is a growing body of evidence to suggest that V. vulnificus and V. parahaemolyticus infections are increasing, and tend to follow regional climatic trends, with outbreaks typically following episodes of unusually warm weather. Such findings are especially alarming given current predictions regarding warming of marine waters as a result of global climatic change. Second, a myriad of epidemiological factors may greatly increase the incidence as well as clinical burden of these pathogens - including increasing global consumption and trade of seafood produce coupled to an increase in the number of susceptible individuals consuming seafood produce. Finally, there is currently a lack of detailed surveillance information regarding non-cholerae Vibrio infections in Europe, as these pathogens are not notifiable in many countries, which probably masks the true clinical burden of many human infections. This review will present a pertinent overview of both the environmental occurrence and clinical impact of V. vulnificus and V. parahaemolyticus in Europe.

Contribution of Vibrio parahaemolyticus virulence factors to cytotoxicity, enterotoxicity, and lethality in mice

Vibrio parahaemolyticus, one of the human-pathogenic vibrios, causes three major types of clinical illness: gastroenteritis, wound infections, and septicemia. Thermostable direct hemolysin (TDH) secreted by this bacterium has been considered a major virulence factor of gastroenteritis because it has biological activities, including cytotoxic and enterotoxic activities. Previous reports revealed that V. parahaemolyticus strain RIMD2210633, which contains tdh, has two sets of type III secretion system (T3SS) genes on chromosomes 1 and 2 (T3SS1 and T3SS2, respectively) and that T3SS1 is responsible for cytotoxicity and T3SS2 is involved in enterotoxicity, as well as in cytotoxic activity. However, the relative importance and contributions of TDH and the two T3SSs to V. parahaemolyticus pathogenicity are not well understood. In this study, we constructed mutant strains with nonfunctional T3SSs from the V. parahaemolyticus strain containing tdh, and then the pathogenicities of the wild-type and mutant strains were evaluated by assessing their cytotoxic activities against HeLa, Caco-2, and RAW 264 cells, their enterotoxic activities in rabbit ileal loops, and their lethality in a murine infection model. We demonstrated that T3SS1 was involved in cytotoxic activities against all cell lines used in this study, while T3SS2 and TDH had cytotoxic effects on a limited number of cell lines. T3SS2 was the major contributor to V. parahaemolyticus-induced enterotoxicity. Interestingly, we found that both T3SS1 and TDH played a significant role in lethal activity in a murine infection model. Our findings provide new indications that these virulence factors contribute to and orchestrate each distinct aspect of the pathogenicity of V. parahaemolyticus.

A real-time PCR assay for the rapid determination of 16S rRNA genotype in Vibrio vulnificus

In a terminal restriction fragment polymorphism (T-RFLP) study, we recently reported a significant association between the type B 16S rRNA gene and clinical strains of Vibrio vulnificus associated with the consumption of raw oysters. In the present study we describe a real-time PCR assay for the rapid determination of the 16S rRNA type of V. vulnificus isolates. This assay was used to reexamine the 16S rRNA gene type in the strains studied previously by T-RFLP and additional isolates from selected sources. Analyses revealed that 15 of the strains (10 environmental and 5 clinical) previously found to be 16S rRNA type A actually appear to possess both the type A and B genes. The presence of both alleles was confirmed by cloning and sequencing both gene types from one strain. To our knowledge, this is the first report of 16S rRNA sequence heterogeneity within individual strains of V. vulnificus. The findings confirm the T-RFLP data that 16S rRNA type may be a useful marker for determining the clinical significance of V. vulnificus in disease in humans and cultured eels. The real-time PCR assay is much more rapid and less resource-intensive than T-RFLP, and should facilitate further study of the occurrence and distribution of the 16S rRNA genotypes of V. vulnificus. These studies should provide more definitive estimates of the risks associated with this organism and may lead to a better understanding of its virulence mechanism(s).

Heterogeneity among isolates of Vibrio vulnificus recovered from eels (Anguilla anguilla) in Denmark

The findings of this study demonstrate that Vibrio vulnificus isolates recovered from diseased eels in Denmark are heterogeneous as shown by O serovars, capsule types, ribotyping, phage typing, and plasmid profiling. The study includes 85 V. vulnificus isolates isolated from the gills, intestinal contents, mucus, spleen, and kidneys of eels during five disease outbreaks on two Danish eel farms from 1995 to 1997, along with a collection of 12 V. vulnificus reference strains. The results showed that more than one serovar may be capable of causing disease in eels and that these isolates are genetically heterogenous as shown by ribotyping. Ribotyping also showed that the same isolates may persist in an eel farm and cause recurrent outbreaks. Phage typing did not correlate with ribotyping or serotyping. However, we observed that 26 of 28 isolates, which were not susceptible to any of the phages, showed the same ribotype, O serovar, and capsule type. This suggests that these isolates may possess features that make them resistant to lysis by the phages used in this study. Ninety-three of 97 isolates harbored between one and three high-molecular-weight plasmids which previously had been suggested to be associated with eel virulence. The subdivision of V. vulnificus into two biotypes based on the indole reaction can no longer be supported, since 82 of 97 isolates in this study were indole positive, and a subdivision into serovars appears to be more correct.

Necrotizing fasciitis caused by Vibrio vulnificus differs from that caused by streptococcal infection

We reviewed the clinical record of all patients admitted to Saga Medical School Hospital during the most recent 10 years and found that 17 (0.03%) were diagnosed as having necrotizing fasciitis. Bacteriological examination demonstrated that Vibrio vulnificus was the pathogen responsible in five patients (29%). The disease caused by V. vulnificus occurred in the warmer half of the year. All of the patients had underlying chronic liver dysfunction, and three of them had previously consumed raw seafood. In these patients, the predominant skin lesions were oedema and subcutaneous bleeding, such as ecchymosis and purpura, while superficial necrosis was not recognized. Three patients died of systemic complications. By contrast, all of the five patients with necrotizing fasciitis caused by Streptococcus pyogenes had the disorder in winter, and only one of them had chronic liver dysfunction. In skin lesions, subcutaneous bleeding was rare but necrosis was seen often. Despite the high incidence of systemic complications, no patients with streptococcal necrotizing fasciitis died. These findings suggest that the clinical features of necrotizing fasciitis caused by V. vulnificus are different from those of necrotizing fasciitis caused by classical pathogens, and that the two should be differentiated as early as possible to improve the prognosis.

Occurrence of Vibrio vulnificus biotypes in Danish marine environments

During the unusually warm summer in Denmark in 1994, 11 clinical cases of Vibrio vulnificus infection were reported. These reports initiated an investigation of the occurrence of V. vulnificus biotypes in Danish marine environments. Samples of coastal water, sediment, shellfish, and wild fish were analyzed by preenrichment in alkaline peptone water amended with polymyxin B (2.0 x 10(4) U/liter) followed by streaking onto modified cellobiose-polymyxin B-colistin agar. V. vulnificus-like colonies were tested with a V. vulnificus-specific DNA probe. Low densities of V. vulnificus were detected in water (0.8 to 19 CFU/liter) from June until mid-September and in sediment (0.04 to > 11 CFU/g) from July until mid-November. The presence of V. vulnificus was strongly correlated with water temperature. However, we isolated V. vulnificus from water from a mussel farm at a lower temperature than previously reported (7 degrees C). In 1 of the 13 locations studied, V. vulnificus was found in mussels in 7 of 17 samples analyzed; this is the first report of V. vulnificus in European shellfish. V. vulnificus was also isolated from gills, intestinal contents, and mucus from wild fish. Although biotyping of 706 V. vulnificus strains isolated during our investigations revealed that the majority of the strains (99.6%) belonged to biotype 1, biotype 2 was detected in seawater at a low frequency (0.4%). Our findings provide further evidence that seawater can serve as a reservoir and might facilitate spread of V. vulnificus biotype 2 to eels, with subsequent spread to persons handling eels. In conclusion, our data demonstrate that V. vulnificus is ubiquitous in a temperature marine environment and that V. vulnificus biotype 2 is not strictly confined to eels.

Does Vibrio vulnificus present a health threat to Canadians?

OBJECTIVE

To review recent data on Vibrio vulnificus and its properties, characteristics of disease and epidemiology, sources of infection, population at risk, infectious dose, documented cases of infection and health risk from V vulnificus infection in Canada.

DATA SOURCE

A MEDLINE and CURRENT CONTENTS search (1981 through September 1996) using the main heading 'Vibrio vulnificus', 'Vibrio species', 'seafood', etc. Relevant articles were also selected from the literature collection in the authors' laboratory.

STUDY SELECTION AND DATA EXTRACTION

The authors judged articles relevant to the objective of the paper and selected them for a review.

DATA SYNTHESIS

V vulnificus, an important cause of septicemia, wound infections and gastroenteritis, is considered to be one of the most invasive and rapidly lethal human pathogens. Molluscan shellfish concentrate this organism from warm seawater and present the greatest danger to consumers. Infections with this pathogen have been reported throughout the world. Most deaths have resulted from the consumption of raw or undercooked oysters, fewer from contact with seawater. Individuals with underlying disease, particularly those with liver diseases and iron overload, are the most susceptible.

CONCLUSION

The two reported cases of V vulnificus wound infection in Canada might not represent the real situation. Infection with this organism may go unrecognized, unreported or simply may not occur. Medical professionals need to become aware of this pathogen and the dire consequences of infection in individuals with underlying disease.

Phenotypic and genotypic characterization of Vibrio vulnificus: proposal for the substitution of the subspecific taxon biotype for serovar

The classification of Vibrio vulnificus strains into two biotypes has been maintained on the basis of phenotypic properties and eel virulence. Biotype 2 is virulent for eels, negative for the indole reaction, and serologically homogeneous (serogroup E), whereas strains of biotype 1 are avirulent, indole positive, and serologically heterogeneous. In the present study, we phenotypically and genotypically characterized 21 V. vulnificus isolates, recovered mainly from northern Europe, by comparing them with reference strains of both biotypes to look for new isolates of biotype 2. The results of this work revealed that the majority of isolates virulent for eels presented phenotypic traits previously considered characteristics of biotype 2 and specific ribotypes with HindIII. However, among the new isolates we found (i) a serogroup E strain virulent for eels but indole positive and (ii) one isolate not belonging to serogroup E but pathogenic for eels. Since no biochemical test for specific serogroup can with certainty be associated with eel virulence, we propose to classify V. vulnificus strains into serovars instead of biotypes. Thus, we suggest serovar E as the denomination of those strains previously classified as biotype 2. Finally, the occurrence of serogroup E in eels cultured in Norway and Sweden, as well as from human infections and shrimp, has been demonstrated.

Effect of low temperature on starvation-survival of the eel pathogen Vibrio vulnificus biotype 2

At present, no reports exist on the isolation of the eel pathogen Vibrio vulnificus biotype 2 from water samples. Nevertheless, it has recently been demonstrated that this biotype can use water as a route of infection. In the present study, the survival of this pathogen in artificial seawater (ASW) microcosms at different temperatures (25 and 5 degrees C) was investigated during a 50-day period, with biotype 1 as a control, V. vulnificus biotype 2 was able to survive in the culturable state in ASW at 25 degrees C in the free-living form, at least for 50 days, entering into the nonculturable state when exposed to low temperature. In this state, this microorganism survived with reduced rates of activity, showing marked changes in size and morphology. The rate at which cells became nonculturable was dependent on their physiological age. The capsule seems not to be necessary for the survival of biotype 2 in aquatic environments as a free-living organism. Culturability remained the highest on modified salt water yeast extract agar, which is closer in salt and nutrient composition to ASW than heart infusion agar. Biotype 2 cells recovered culturability on solid media after an increase of incubation temperature from 5 to 25 degrees C. Culturable cells of this bacterium maintained infectivity for either eel or mice, while dormant cells seemed to lose their virulence. The former finding suggests that the aquatic environment is a reservoir and vehicle of transmission of this pathogen.

First documented case of bacteremia with Vibrio vulnificus in Sweden

A few days after a mild trauma to a toe, a 90-year-old woman presented with fever, malaise and cellulitis. On suspicion of erysipelas the patient was initially treated with benzylpenicillin and cefuroxime. Her general condition improved rapidly, but there was local progression with numerous necrotic areas with surrounding bullae. Vibrio vulnificus was isolated from the blood. After susceptibility testing, the patient was finally treated with ciprofloxacin and pivampicillin, and recovered slowly. To our knowledge, this is the first reported case of bacteremia with V. vulnificus in Sweden.

Seasonal variations in the occurrence of Vibrio vulnificus along the Dutch coast

The seasonal variation in the occurrence of V. vulnificus in relation to water temperature and salinity was studied along the Dutch coast. In two consecutive years V. vulnificus strains could be isolated in August when the water temperature was highest. The indole-positive strains isolated from North Sea water samples were identical to most strains isolated from human disease and from the environment. However, strains isolated from four of five patients living in countries around the North Sea were different from the North Sea isolates in that they were indole-negative and have a lower NaCl tolerance.

Identification of Vibrio vulnificus O serovars with antilipopolysaccharide monoclonal antibody

A serotyping scheme for Vibrio vulnificus predicated on the detection of lipopolysaccharide (LPS) antigens is proposed. The serovar O typing scheme used to type V. vulnificus employs polyclonal antisera raised in rabbits immunized with heat-killed whole-cell vaccines. Polyclonal typing sera produced in this manner cross-react with heterologous strains. Affinity purification of polyclonal antisera with LPS affinity columns resolved some of these cross-reactions; however, affinity-purified polyclonal antisera still showed cross-reactions that were nonreciprocal. On the basis of the serological patterns that were obtained with affinity-purified polyclonal antisera, V. vulnificus strains were selected as vaccine strains for production of monoclonal antibody. Spleen cells harvested from BALB/c mice immunized with formalin-killed V. vulnificus cells were fused with SP2/O-Ag 14 myeloma cells. Hybridomas were screened by using LPS and whole-cell enzyme-linked immunosorbent assay to identify clones secreting LPS-specific antibodies. Monoclonal antibodies identified five LPS serological varieties of V. vulnificus and a single serovar each for Vibrio damsela and Vibrio hollisae. No cross-reactions between V. vulnificus and V. hollisae or V. damsela were observed.

Vibrio vulnificus infection in Hawaii

A life-threatening Vibrio vulnificus infection occurred in a 52-year-old Korean woman with hepatic cirrhosis. Four days after ingesting raw crab, the patient presented to the hospital with nausea, vomiting, fever, hypotension, and hemorrhagic blistering of the left foot. Vibrio vulnificus was recovered from both her blood and a foot wound.

Vibrio vulnificus infection

We report 3 cases of Vibrio vulnificus infections from Taiwan. Patient 1, who manifested symptoms of primary septicemia, died after 2 days. Patient 2, who had a wound infection and signs and symptoms of sepsis but negative blood cultures, responded to tobramycin and chloramphenicol plus surgical debridement, and recovered after 26 days of hospitalization. Patient 3 had secondary septicemia originating from a wound inflicted by a shrimp. Originally, the patient seemed to respond to ceftazidime and amikacin treatment along with surgical debridement, but subsequently died from adult respiratory distress syndrome (ARDS) induced by several episodes of aspiration which occurred after initial clinical improvements. We conclude that, for patients with severe wounds and evidence of V. vulnificus infection, an appropriate, powerful antibiotic, such as one of the third generation cephalosporins should be used as initial therapy unless the nature of the infection indicates other treatment.

Septicaemia caused by Vibrio vulnificus

Vibrio vulnificus is an uncommon cause of septicaemia. A few reports suggest that patients with chronic liver disease are more susceptible. We report two cases of septicaemia caused by this organism and emphasise the need for early empirical therapy.

Acute hepatic failure precipitated in a patient with subclinical liver disease by vibrionic and clostridial septicemia

A case of fatal septicemia caused by Vibrio vulnificus and Clostridium bifermentans in a patient with subclinical liver disease is described. The patient appeared to recover from the infection initially after antibiotic therapy but finally succumbed to rapidly developing hepatic failure. Postmortem examination revealed hemochromatosis. The pathogenesis of the polymicrobial septicemia and hepatic failure is discussed in the light of the published literature.

Bacteriology of the marine environment: implications for clinical therapy

Ocean water and tissue samples were obtained from a variety of sources with phylogenetic and geographic diversity. Purified bacterial colonies were isolated and identification procedures were performed. A total of 67 isolates were recovered. Thirty-eight isolates belonged to the genus Vibrio and included six species. Twenty-four non-fermentative bacteria and four Gram-positive isolates were recovered. Antibiotic susceptibility testing showed that while the non-fermentative marine bacteria generally were susceptible to the antibiotics tested, marine Vibrio species were relatively resistant to a wide variety of antimicrobials. Antibiotics effective against all species included imipenem, trimethoprim/sulfamethoxazole, and chloramphenicol. Further recommendations for treatment are based on sensitivity in culture. Some isolates failed to grow in the medium used for susceptibility testing. Because commercial test kits may not yield accurate identifications of bacteria, the acquisition of antimicrobial susceptibility data gains added importance.

Inhibitory effect of capsular antigen of Vibrio vulnificus on bactericidal activity of human serum

Opaque (Op) and translucent (Tr) colonial variants were isolated from Vibrio vulnificus strains. Op-type variants were more resistant than the isogenic Tr-type variants, but the survival rate of the Op-type variants varied with the strains. Antisera were prepared by immunizing rabbit with whole cells of Op and Tr variants of some strains, in which the difference of the sensitivity between Op and Tr cells was remarkable. Then agglutination tests with their living and heat-killed cells were carried out. The results suggested the presence of capsular antigen in Op cells and its absence in Tr cells, with the exception of the existence of a slight amount of capsular material in Tr variants of strain L-180. The thin capsular layer of Tr cells of strain L-180 was also demonstrated electron microscopically, but the layer was thinner than that of the isogenic Op cells. Results of determination of sugar content in the extracted capsular fraction also showed that Op to Tr transformation was due to loss of capsular antigen of the cells. These results confirmed the morphological studies previously reported which suggested the prevention of host defense system by the capsular material of the vibrio.

Occurrence and distribution of halophilic vibrios in subtropical coastal waters of Hong Kong

The summer occurrence and distribution of halophilic vibrios in the subtropical coastal waters of Hong Kong were investigated. The density of vibrios in six sample sites ranged from 90 to 6,700 per ml, which made up 0.41 to 40% of the total bacterial populations of these sample sites. The sucrose-positive vibrios were found to be much more common (88% of total vibrios) than the sucrose-negative ones. A total of 48 strains belonging to six Vibrio species were fully characterized. Among these, Vibrio alginolyticus was the most frequently isolated, followed by V. parahaemolyticus, V. harveyi, V. vulnificus, V. campbellii, and V. fluvialis. The finding that eight of the nine strains of V. harveyi showed a positive Kanagawa reaction warrants further study.

Gastroenteritis in patients with stool isolates of Vibrio vulnificus

Vibrio vulnificus, a marine Vibrio associated with severe extraintestinal infections, has not been previously implicated as a cause of infectious diarrhea. Three patients were identified with diarrheal illness from whom this organism was the sole pathogen recovered from cultured stool specimens. All three had eaten raw oysters within one week of becoming ill. These patients were all taking medication that reduces gastric acidity, two were heavy drinkers of alcohol, and one had unrecognized colon cancer; these factors may have predisposed to the development of disease. Clinicians should consider that V. vulnificus may be a cause of gastroenteritis in patients who have consumed raw oysters.

Some properties of Vibrio vulnificus hemolysin

Some properties of hemolysin produced by Vibrio vulnificus were investigated. The hemolysin was heat labile, and the hemolytic activity was inhibited by adding cholesterol or divalent cations. Cholesterol inhibited the temperature-independent hemolysin-binding step, suggesting that cholesterol made up the binding site of the cell membrane, whereas the divalent cations inhibited the temperature-dependent membrane-degradation step. However, the V. vulnificus hemolysin was stable to oxygen and sulfhydryl reagents and was not inactivated by antiserum against streptolysin O, suggesting that the V. vulnificus hemolysin differs from oxygen-labile hemolysins which bind to cholesterol. The V. vulnificus hemolysin seems to be one of the exceptional cholesterol-binding hemolysins.

Vibrio vulnificus septicemia

A 33-year-old Japanese male, who had a three year history of biopsy-proved liver cirrhosis, was admitted to the hospital on June, 24, 1983 with a sudden onset of fever (38.6 degrees C), chills, generalized pain, nausea, anorexia, weakness, and eruption over the entire body. The patient went into shock and died about 7 hours after admission. Blood cultures before death were positive for V. vulnificus. Postmortem microscopic examination revealed "necrotizing vasculitis" in the small and large intestines, stomach, and skin, and also showed marked toxic epidermal necrolysis. This case matches the primary septicemia caused by V. vulnificus described by Blake et al. In addition, this case suggests that the septicemia was acquired through the gastrointestinal tract, especially the small intestine, because the V. vulnificus was isolated from blood and numerous Gram-negative bacilli around the submucosal vessels were observed in the area with acute necrotizing vasculitis.

Necrotising fasciitis caused by Vibrio vulnificus

A case of necrotising fasciitis caused by Vibrio vulnificus is described. The need for early recognition and aggressive surgical treatment are highlighted, and the necrotising infections due to V vulnificus described in the published work are reviewed.

Vibrio hand infections: a case report and review of the literature

A case of Vibrio vulnificus infection of the hand is presented. The role of Vibrio species as primary pathogens in infections associated with exposure to a marine environment is discussed.

Protection of mice against Vibrio vulnificus disease by vaccination with surface antigen preparations and anti-surface antigen antisera

Vaccination of mice with either Formalin-killed cells or cell extracts of a virulent strain and a weakly virulent strain of Vibrio vulnificus or with rabbit antisera (AS) against the Formalin-killed cells and cell extracts protected against the virulent strain of V. vulnificus. However, the virulent strain vaccines and AS elicited a significantly stronger immune response than the weakly virulent strain vaccines and AS. Adsorption of the AS with either the homologous or heterologous Formalin-killed cells significantly reduced the ability of the AS to protect mice. The major protective antigen(s) in the cell extracts migrated in the void volume of Sephacryl S-400 superfine, was not effectively sedimented by centrifugation at 100,000 X g for 2 h, had an isoelectric point of 3.8 to 4.2, and was sensitive to boiling or autoclaving for 15 min, periodate oxidation, and exposure to pH 12 but was resistant to 56 degrees C, trypsin, pronase, RNase, neuraminidase, and pH 4.5. Electron microscopy revealed that the virulent strain possessed a more dense ruthenium red-staining layer on its outer membrane and had a much smoother surface than the weakly virulent strain. Our results provide evidence that a major protective antigen and virulence factor of V. vulnificus is a heat-labile, acidic polysaccharide located on the bacterial surface.

Extracellular phospholipase A2 and lysophospholipase produced by Vibrio vulnificus

Phospholipase A2 and lysophospholipase activities were detected in the culture supernatant fluids of a virulent strain of Vibrio vulnificus. The phospholipase A2 was inactivated by heating at 56 degrees C for 30 min, had an apparent molecular weight of greater than or equal to 80,000 (estimated by gel filtration with Sephadex G-75), and a pI of ca. 5.0. Phospholipid hydrolysis was unaffected by Ca2+ or ethylene glycol-bis(beta-aminoethyl ether)-N,N-tetraacetic acid and was optimal at pH 5.0 to 5.5. The lysophospholipase was not affected by heating at 56 degrees C for 30 min but was inactivated at 100 degrees C and had an apparent molecular weight of greater than or equal to 80,000 and a pI of ca. 4.0. The enzymes were detected coincidentally with a previously described extracellular cytolysin of V. vulnificus; however, they were physically separable from the toxin (which did not possess phospholipase A, C, or D activity) by gel filtration with Sephadex G-75.

Comparative studies and laboratory diagnosis of Vibrio vulnificus, an invasive Vibrio sp

Vibrio vulnificus was isolated from a bacteremic patient. This strain, together with other isolates of V. vulnificus, was compared with V. alginolyticus, V. fluvialis, and V. parahaemolyticus with regard to growth characteristics on enteric agar media (enabling isolation and identification) and production of exoenzymes which could correlate with invasive potential. V. vulnificus grew well on MacConkey. Endo, xylose-lysine deoxycholate, and Hektoen enteric agar plates. Because V. vulnificus colonies resembled those of lactose-fermenting strains of the family Enterobacteriaceae, however, isolation of this vibrio from mixed specimens or stools may require the use of thiosulfate-citrate-bile salts-sucrose agar. V. vulnificus produced numerous exoenzymes (protease, DNase, lipase, and esterase) but not elastase or lecithinase. Although differences in exoenzyme production were observed among the four vibrio species, no single exoenzyme could be linked to the invasive potential of V. vulnificus.

Differential complement activation and susceptibility to human serum bactericidal action by Vibrio species

The ability of Vibrio vulnificus to resist human serum bactericidal action and to activate human complement was compared with similar cultures of Vibrio cholerae and Vibrio parahaemolyticus. Both V. vulnificus and V. parahaemolyticus had similar survival rates in sera and were much more resistant to killing than was V. cholerae. In contrast, V. vulnificus activated significantly less serum complement than did V. cholerae and V. parahaemolyticus. The relative ability of V. vulnificus to survive in serum and activate less complement than other Vibrio spp. tested may be related to its ability to cause chronic tissue infections and septicemias.

Vibrio vulnificus infection. Case report and update since 1970

Vibrio vulnificus infections is being reported with increasing frequency in coastal regions of the United States. Raw seafood consumption, particularly raw oysters, and wounds acquired in a marine environment predispose to infection. Patients with advanced liver disease are at increased risk of developing septicemia. V. vulnificus is a virulent pathogen producing significant morbidity and mortality; its virulence relates in part to the production of exotoxin. Skin lesions occur early in the clinical course of infection and provide means of specific diagnosis. The patient and the consulting physician are well served by the dermatologist capable of recognizing this infectious disease.

Distribution of Vibrio vulnificus and other lactose-fermenting vibrios in the marine environment

During the summer of 1981, 3,887 sucrose-negative vibrios were isolated from seawater, sediment, plankton, and animal samples taken from 80 sites from Miami, Fla., to Portland, Maine. Of these, 4.2% were able to ferment lactose. The lactose-positive strains isolated from the various samples correlated positively with pH and turbidity of the water, vibrios in the sediment and oysters, and total bacterial counts in oysters. Negative correlations were obtained for water salinity. Numerical taxonomy was performed on 95 of the lactose-fermenting environmental isolates and 23 reference strains. Five clusters resulted, with the major cluster containing 33 of the environmental isolates and all of the Vibrio vulnificus reference strains. The 33 isolates, which produced an acid reaction in lactose broth within hours of initial inoculation, represented 20% of all lactose-fermenting vibrios studied. These isolates were nearly identical phenotypically to clinical strains of V. vulnificus studied by the Centers for Disease Control, Atlanta, Ga., and by our laboratory, and their identification was confirmed by DNA-DNA hybridization studies. V. vulnificus was isolated from all sample types and from Miami to Cape Cod, Mass., and comparison of the environmental parameters of the eight subsites yielding this species with those of all 80 subsites revealed no significant differences. The majority of the isolates were obtained from animals, with clams providing most (84%) of these. On injection into mice, 82% of the V. vulnificus isolates resulted in death. Members of the remaining four clusters contained strains which differed from V. vulnificus in such phenotypic traits as luminescence and in urease or H(2)S production. None of the other reference cultures, including nine other Vibrio species, were contained in the remaining clusters, and these isolates could not be identified. Most of these were also lethal for mice. Phenotypic differences, potential pathogenicity, and geographic distribution of the five clusters were examined. It is concluded that V. vulnificus is a ubiquitous organism, both geographically and in a variety of environmental sources, although it occurs in relatively low numbers. The public health significance of this organism and of the other unidentified lactose-fermenting Vibrio species is discussed.

Distribution and ecology of Vibrio vulnificus and other lactose-fermenting marine vibrios in coastal waters of the southeastern United States

Water, sediment, plankton, and animal samples from five coastal sites from North Carolina to Georgia were sampled for their lactose-fermenting vibrio populations. Over 20% of all vibrios tested were sucrose negative and o-nitrophenyl-beta-D-galactopyranoside (ONPG) positive, suggesting identification as the human pathogen Vibrio vulnificus. These vibrios were isolated from all sample sites and sources (water, sediment, plankton, and animals). Correlations with several of 19 environmental parameters monitored at each site were found for total vibrios. The presence of ONPG-positive, sucrose-negative vibrios was correlated with hydrocarbon levels in the water and, in the case of plankton samples, with salinity. A total of 279 sucrose-negative, ONPG-positive isolates were subjected to numerical taxonomic analysis, which resulted in three major clusters. Cluster I corresponded to and included 11 reference strains of V. vulnificus. Cluster II contained the largest number (133) of isolates, of which the great majority were bioluminescent. Although having a resemblance to V. harveyi, the isolates were ONPG positive and many were H2S positive. Cluster III consisted of strains similar to the group F vibrios (V. fluvialis). Of all of the isolates, 55% were luminescent, of which over 20% were lethal when injected into mice. Problems involved in detecting lactose fermentation among marine vibrios and the potential pathogenicity of these organisms are discussed.

Vibrio parahaemolyticus and related halophilic Vibrios

Approximately 30 years have elapsed since Dr. Fujino's original discovery that Vibrio parahaemolyticus (then termed Pasteurella parahemolytica) was the cause of "summer diarrhea" in Japan. Since that finding, V. parahaemolyticus has been established as a cause of gastroenteritis in numbers and places approaching global proportions. It has been isolated in marine and estuarine areas almost worldwide and despite its halophilic nature, V. parahaemolyticus has been isolated from saline-free waters. The relationship of this organism to the environment reveals a close association with other marine organisms especially copepods on which the Vibrios depend for survival in winter months and growth in summer months. There is a uniquely provocative disparity between human strains of V. parahaemolyticus which are Kanagawa phenomenon (KP) positive and the environmental strains which to a large extent are KP negative, the significance being that pathogenicity is measured according to the Kanagawa phenomenon (hemolytic activity) reaction. The hemolysin of the pathogenic strains is a thermostable, cardiotoxic protein, which thus far has not been implicated in the mechanism(s) which causes human gastroenteritis. The interest in this organism has been widened in recent years by the finding that similar organisms, V. alginolyticus, lactose positive vibrios and group F vibrios also cause serious disease in humans.

Partial Purification and Characterization of Hemolysin from a Psychrotrophic Kanagawa-Positive Marine Vibrio

Psychrotrophic Kanagawa-positive marine vibrios were isolated from soft-shelled clams ( Mya arenaria ) collected in Yaquina Bay, Oreg. The 235 vibrio isolates obtained were screened for Gram reaction and morphology, Kanagawa reaction on Wagastsuma agar, and response to selected biochemical tests. The vibrio selected for further study was grown in broth, and the hemolysin was precipitated from a cleared supernatant with solid ammonium sulfate. The hemolytic substance was partially purified by DEAE-cellulose and Sephadex G-100 column chromatography. The hemolysin contained protein essential for activity, was thermolabile, and was more active against rabbit erythrocytes at 37°C than at lower temperatures. The molecular weight was estimated at 55,000 by using a Sephadex G-100 column. Hemolytic activity was partially inactivated by gangliosides and lowered against horse erythrocytes. The hemolysin did not react with antibody prepared against vibriolysin from Vibrio parahaemolyticus WP-1 by the Ouchterlony method. The hemolysin was high in aspartic and glutamic acids and low in arginine and histidine. Electrophoresis on a sodium dodecyl sulfate-polyacrylamide gel gave three major bands. The hemolysin from a psychrotrophic vibrio and the hemolytic exotoxin of V. parahaemolyticus had some similar and dissimilar characteristics. The possibility that a Vibrio sp. other than V. parahaemolyticus might serve as the reservoir for the Kanagawa phenotype is discussed.

A Halophilic vibrio isolated from a case of chronic cholecystitis

We found a halophilic vibrio in B bile from a 75-year-old female patient with chronic cholecystitis, and examined its biochemical characteristics. The organisms are gram-negative short rods or comma shaped, with some ring forms. They have a single polar flagellum, but not capsule. The strains can grow in peptone water with 1.0 to 4.0% NaC1, but not with no NaC1 or 6.0% NaC1. The characteristics of the organisms are positive dextrose fermentation, catalase, oxidase, and ornithine decarboxylase, and negative lysine decarboxylase, arginine dihydrolase, and absence of gas from glucose. They are sensitive to 2,4-diamine-6,7-diisopropyl pteridine (0/129). These characteristics indicate that the isolated strain should be a halophilic vibrio. however, no growth on Salmonella-Shigella (SS), SS with added sucrose and bromcresol purple (SS-SB), MacConkey's or thiosulfate citrate bile salts (TCBS) agar plates was demonstrated. Nitrate reduction, Simmons' citrate agar, indole, omicron-nitrophenol-beta-d-galactopyranoside (ONPG), motility and esculin hydrolysis were positive. Urease, gelatinase, Voges-Proskauer, phenylalanine deaminase and malonate reactions were negative. Acid was produced from amygdalin, arabinose, cellobiose, fructose, galactose, glucose, lactose, maltose, mannitol, salicin, starch, sucrose, trehalose, and xylose, but not from adonitol, dulcitol, inositol, mannose, melibiose, raffinose, rhamnose and sorbitol. From these characteristics the isolate is considered to be not identical with V. parahaemolyticus, V. Cholerae, V. Vulnificus or other vibrios. It can be presumed that this isolate represents another species of halophilic vibrio.

Hemolytic reaction of clinical and environmental strains of Vibrio vulnificus

All Vibrio vulnificus strains tested (four clinical isolates and eight environmental isolates) hemolyzed human erythrocytes. In contrast to findings with Vibrio parahaemolyticus, in which hemolytic activity correlates with isolation from clinical specimens, results from the present study suggest that hemolysis is not usefull in differentiating V. vulnificus strains.