Current perspectives on the epidemiology and pathogenesis of clinically significant Vibrio spp

Contribution to some phenotypical characteristics of Vibrio cincinnatiensis. Studies in one strain of a diarrhoeic human patient and in two isolates from aborted bovine fetuses

Until now, only a few strains of V. cincinnatiensis have been isolated. This study describes a further three isolates which originated in one case from a stool specimen of an immunocompromised elder patient suffering from enteritis and in two cases from the rennin stomachs of aborted bovine fetuses. These strains grew on TCBS, CIN, MacConkey and XLD plates. Their biochemical activities were dependent on NaCl concentration, in particular the formation of indole, lysine and ornithine decarboxylases, arginine dihydrolase, the reduction of nitrate and behaviour in the Voges-Proskauer test. Moreover, lysine decarboxylase and nitrate reductase were temperature-dependent. The knowledge of these hitherto unknown phenotypical characteristics may facilitate the diagnosis of the pathogen.

Severe human infections caused by Vibrio metschnikovii

Vibrio metschnikovii is largely distributed in the aquatic environment; human infections are rarely observed. A fatal case of septicemia in a patient with liver cirrhosis, renal insufficiency, and diabetes is described. A second case in a 82-year-old woman with septicemia, respiratory problems, and infected leg lesions is reported; she was successfully treated.

Vibrio parahaemolyticus has a homolog of the Vibrio cholerae toxRS operon that mediates environmentally induced regulation of the thermostable direct hemolysin gene

In an effort to identify the regulatory gene controlling the expression of the tdh gene, encoding the thermostable direct hemolysin of Vibrio parahaemolyticus, we examined total DNA of AQ3815 (a Kanagawa phenomenon-positive strain) for sequences homologous to that of the toxR gene of Vibrio cholerae. The extracted DNA gave a weak hybridization signal under reduced-stringency conditions with a toxR-specific DNA probe. Cloning and sequence analysis of the probe-positive sequence revealed an operon (Vp-toxRS) which was highly similar to the toxRS operon of V. cholerae (Vc-toxRS) (52 and 62% similarities in the two genes, respectively). The deduced amino acid sequences of the Vp-toxRS gene products (Vp-ToxRS) contained regions similar to the proposed transmembrane and activity domains of the Vc-toxRS gene products (Vc-ToxRS). All clinical and environmental strains of V. parahaemolyticus examined possessed the Vp-toxRS genes. In the presence of Vp-ToxS, Vp-ToxR promoted expression of the tdh2 gene, one of two tdh genes (tdh1 and tdh2) carried by Kanagawa phenomenon-positive strains. The DNA sequence located 144 bp upstream of the tdh2 coding region was shown to be important for the Vp-ToxR-stimulated expression of the tdh2 gene in an Escherichia coli background. Comparative analysis of AQ3815 and its isogenic Vp-toxR null mutant gave the following results: (i) Vp-ToxR promoted, in an AQ3815 background, expression of the tdh gene to different degrees in various culture media, with KP broth (2% peptone, 0.5% NaCl, 0.03 M KH2PO4, pH 6.2) being most effective (12-fold); (ii) the promotion of tdh gene expression in KP broth was at the level of transcription; and (iii) Vp-ToxR was essential for demonstration of enterotoxic activity of AQ3815 in the rabbit ileal loop, a model previously used to demonstrate thermostable direct hemolysin-mediated enterotoxic activity of AQ3815. These results demonstrate that Vp-ToxR and Vc-ToxR share a strikingly similar function, i.e., direct stimulation at the transcriptional level of the gene encoding a major virulence determinant (enterotoxin) of a Vibrio species.

Fatal necrotizing fasciitis due to Vibrio damsela

A patient who succumbed to fulminant necrotizing fasciitis due to Vibrio damsela after injury by a rabbitfish is described. Despite the absence of any known underlying illness, he did not respond to appropriate antibiotic therapy and radical surgical intervention. This represents the first documented case of necrotizing fasciitis due to this organism, and is also the first reported case in Southeast Asia inflicted by rabbitfish.

Features of cholera and Vibrio parahaemolyticus diarrhoea endemicity in Calabar, Nigeria

The clinical and epidemiological features of acute vibrio diarrhoeal disease were studied in 881 patients seen at the University of Calabar Teaching Hospital (UCTH), Calabar, Nigeria, between January and December 1989. Stools and rectal swabs of patients and randomly-selected control subjects were microscopically and culturally examined for the presence of enteric pathogens. Households of vibrio diarrhoea cases and matched controls were visited for ecologic studies. Of a total of 108 (12.3%) culturally-confirmed bacterial diarrhoeas, 47 (43.5%) were due to Escherichia coli, 33 (30.6%) to Vibrio cholerae-01 (classical and El Tor biotypes) and V. parahaemolyticus, while shigellae and salmonellae accounted for 29 (26.9%) and 9 (8.3%) cases, respectively. Most cholera case households clustered within the ancient neighbourhood of the inner city, characterized by poorly developed water and sewage disposal systems. A preponderance of vibrio diarrhoea patients were children < or = 10 years. Adult cases involved mostly females. The only case of diarrhoea-related death involved an eight-month old child with kwashiorkor and V. parahaemolyticus infection. Incidence of vibrio diarrhoeas was seasonal, with most cases occurring during the dry season followed by subsidence at the onset of rainy season. Bimodal peaks of vibrio diarrhoeal episodes observed over the period appeared to coincide with periods of acute water scarcity, high temperature, increased fishing activities and trade traffic on the Calabar River estuary. Of the environments sampled, only clam shells from a case household and river sediments yielded vibrio pathogens on culture. Ecological factors that are capable of stabilizing a focus of vibrio diarrhoea endemicity in this area are highlighted.

Cell surface characteristics of environmental and clinical isolates of Vibrio cholerae non-O1

The cell surfaces of several toxigenic and nontoxigenic environmental and clinical isolates of Vibrio cholerae non-O1 have been examined. The environmental strains, irrespective of toxigenicity, are significantly more resistant to antibiotics and detergents than are V. cholerae O1 strains. The clinical isolates of non-O1 vibrios are as sensitive to a wide variety of chemicals as the O1 vibrios. The environmental non-O1 strains are also less susceptible to lysis when treated with protein denaturants or neutral and anionic detergents than are O1 vibrios and the clinical non-O1 strains. In contrast to O1 vibrios, the environmental non-O1 vibrios do not have exposed phospholipids in their outer membranes. These features of the cell surfaces of environmental non-O1 vibrios might have a role in the better survival of these organisms under environmental fluctuations.

Vibrio-associated gastroenteritis in the lower Cross-River Basin of Nigeria

A total of 120 Vibrio species were isolated from 588 patients with acute diarrheal disease during an outbreak of gastrointestinal tract infections at different locations in the lower Cross River Basin of Nigeria. Vibrio cholerae O1, biotype El Tor, serotype Ogawa, was the prominent organism isolated from the Vibrio-associated diarrheal cases. During the 3 months of study, V. cholerae non-O1 was recovered from 10 patients while Vibrio parahaemolyticus was recovered from 19 patients. The significance of this study is the recognition that there is an ecological niche which supports V. cholerae non-O1 and V. parahaemolyticus in the Cross River Basin of Nigeria.

Enterotoxigenicity of Vibrio parahaemolyticus with and without genes encoding thermostable direct hemolysin

Vibrio parahaemolyticus produces a thermostable direct hemolysin (TDH) that has been implicated in the pathogenesis of diarrheal disease caused by this organism. However, previous studies attempting to demonstrate the contribution of the hemolysin to virulence have been inconclusive. We investigated this putative virulence factor by using an isogenic TDH-negative (TDH-) strain constructed by specifically inactivating the two copies of the tdh gene encoding TDH. The enterotoxigenicities of the parent strain (AQ3815) and the mutant strain were tested by adding sterile culture supernatants to rabbit ileal tissue mounted in Ussing chambers. The culture filtrate of the parent strain produced a significant increase in short-circuit current (Isc), compared with the change induced by the TDH- mutant. The capacity of the culture filtrate of AQ3815 to increase the Isc was reduced by neutralization with anti-TDH serum, and the return of the cloned tdh gene to the TDH- mutant restored the ability to increase the Isc. These results were corroborated by rabbit ileal loop assays in which AQ3815 caused fluid accumulation but the TDH- mutant did not. No microscopic damage was seen in mucosal tissues exposed to the culture filtrate of either strain. These results indicate that TDH has an enterotoxigenic effect on rabbit small intestine and could be responsible for the watery diarrhea seen with V. parahaemolyticus.

Isolation of vibriostatic agent O/129-resistant Vibrio cholerae non-O1 from a patient with gastroenteritis

A strain of Vibrio cholerae non-O1 was isolated from a 48-year-old male in California who presented with a chief complaint of watery diarrhea. Laboratory investigations of this strain revealed the bacterium to be resistant to trimethoprim-sulfamethoxazole and to the vibriostatic agent O/129 (2,4-diamino-6,7-diisopropylpteridine).

Analysis of some virulence factors of Vibrio vulnificus isolated from Rio de Janeiro, Brazil

Twenty strains of V. vulnificus isolated from the environment were investigated for characteristics related to their infectivity such as colonial morphology, enzymatic activity and animal assays. The presence of DNase, chitinase, amylase, lecithinase and gelatinase was observed in 100% of the strains, haemolytic activity was absent, and variable results were obtained in elastase, collagenase and chondroitinase. In the animal assays, 70% of the strains were lethal to adult mice, while 45% caused fluid accumulation in suckling mice. Although all strains had opaque colonies, only 3 of the 20 had the three enzymes elastase, collagenase and gelatinase, and only one of these was virulent in animal assays.

Electrophoretic and chemical characterization of lipopolysaccharides of Vibrio parahaemolyticus

Lipopolysaccharides (LPSs) isolated from three Kanagawa-positive and three negative strains of Vibrio parahaemolyticus were characterized by using electrophoretic, immunochemical, and chemical methods. The results of this study indicated that the LPSs of all six strains of V. parahaemolyticus examined did not have an O-specific side chain. These V. parahaemolyticus LPSs appeared to have molecular weights similar to that of the rough-type (Ra) LPS of Salmonella typhimurium TV-119 and might just contain lipid A and a core region. However, the microheterogeneity of V. parahaemolyticus LPS observed was greater than that of S. typhimurium LPS. The profile of V. parahaemolyticus LPS consisted of closely spaced triplet or quadruplet bands, but that of S. typhimurium consisted of doublet bands. Slower-moving bands appeared on sodium dodecyl sulfate-polyacrylamide gel electrophoresis gels only when large amounts of V. parahaemolyticus LPS were loaded. These bands were proven to be the aggregates of the fastest-moving low-molecular-weight bands by re-electrophoresis. The banding pattern of V. parahaemolyticus LPSs produced on nitrocellulose membranes by immunoblotting indicated that the V. parahaemolyticus LPSs did not have an O-specific side chain. The low ratio of total carbohydrate to lipid A of V. parahaemolyticus LPSs also suggested that they were like rough-type LPS. The mobility and profile of V. parahaemolyticus LPS on sodium dodecyl sulfate-polyacrylamide gel electrophoresis gel and its chemical composition were closely related to the serotype of a specific strain but not with the Kanagawa phenomenon.

A simple purification method of Vibrio cholerae non-O1 hemagglutinin/protease by immunoaffinity column chromatography using a monoclonal antibody

A new simple purification method (I) for Vibrio cholerae non-O1 hemagglutinin/protease (NAG-HA/P) was developed. The method (I) requires only an immunoaffinity column chromatography using a monoclonal antibody against NAG-HA/P. The method (I) is much simpler than previously reported purification method (II) (Honda, T. et al, Infection and Immunity 57: 2799-2803, 1989) which required four or more complicated chromatographic procedures. Method (I) also gave an improved recovery rate (about 27%) compared with (II). The molecular weight of NAG-HA/P purified by method (I) was mainly 34 kilodaltons (kDa) with a little of 32 kDa, whereas that of NAG-HA/P purified by (II) was usually 32 kDa. Immunological analysis by the Ouchterlony double gel diffusion test and Western blotting test using polyclonal antibody against 32 kDa protein revealed that the 34 and 32 kDa proteins are immunologically indistinguishable and thus it is supposed that 34 K protein is an isoform or a preform of the 32 K protein.

Víbrios não coléricos na rotina enterobacteriológica

De 3.250 fezes diarréicas, recebidas para diagnóstico microbiológico em laboratório clínico particular, no Recife, Brasil, isolaram-se 55 (1,7%) linhagens de Vibrio. O estudo foi realizado entre maio de 1989 e maio de 1991. Para o isolamento de Vibrio, os espécimes fecais foram enriquecidos em água peptonada alcalina suplementada com 2% de NaCl e subcultivados em ágar tiosulfato-citrato-sais biliares-sacarose (TCBS). Das espécies isoladas, V. parahaemolyticus foi a mais freqüente (24 cepas), seguida de V. furnissii (15 cepas), V. cholerae não 01 (6 cepas), V. alginolyticus (4 cepas), V. fluvialis (2 cepas) e Vibrio sp. (1 cepa). Do ponto de vista custo-benefício, a baixa taxa de isolamento de Vibrio levanta dúvidas acerca da utilidade do TCBS na rotina enterobacteriológica dos laboratórios clínicos

Occurrence of resistance to vibriostatic compound 0/129 in Vibrio cholerae 01 isolated from clinical and environmental samples in Bangladesh

Fifty-one Vibrio cholerae 01 strains isolated from 734 natural water and plankton samples and 31 rectal swabs were examined. Of these strains, 32 (62.7%) were found to be resistant to vibriostatic compound 0/129. When antibiograms using the antibiotics ampicillin, tetracycline, chloramphenicol, trimethoprim-sulfamethoxazole, furoxan, and gentamicin were done, it was observed that there was a correlation of sensitivity to 0/129 with selected antibiotics. Only the Ogawa E1 Tor (72% of strains resistant) and Inaba classical (28% of strains resistant) biotypes of V. cholerae 01 showed resistance to 0/129. On the other hand, all Inaba E1 Tor and Ogawa classical strains were susceptible to 0/129. The 32 0/129-resistant and 19 0/129-sensitive isolates of V. cholerae 01 were tested for the presence of plasmid DNA. Only two strains isolated from the environment were found to carry a plasmid, and they were also found to be resistant to 0/129 and gentamicin. Thus, 0/129 resistance, although more common than previously suspected, is concluded not to be plasmid mediated in the strains tested in this study.

Contribution of the tdh1 gene of Kanagawa phenomenon-positive Vibrio parahaemolyticus to production of extracellular thermostable direct hemolysin

Kanagawa phenomenon-positive strains of Vibrio parahaemolyticus contain two copies of the tdh gene (tdh 1 and tdh 2) encoding thermostable direct hemolysin (TDH). Previous studies suggested that the tdh 2 gene, but not the tdh 1 gene, was responsible for production of extracellular TDH. In this study, a tdh 2-deficient isogenic mutant of Kanagawa phenomenon-positive strain AQ3815 was constructed by a suicide vector-mediated in vivo recombination method. The intact tdh 1 gene in the mutant contributed little to Kanagawa phenomenon on Wagatsuma agar but produced TDH in broth media, accounting for 0.5-9.4% of total extracellular TDH of AQ3815.

Vibrio vulnificus. Hazard on the half shell

Vibrio vulnificus is an extremely invasive gram-negative bacillus that causes bacteremia and shock. It should be suspected in any patient who is immunocompromised or has liver disease or hemochromatosis. Reduced gastric acidity may also increase the risk of infection if a patient presents with a history of ingesting raw shellfish (especially oysters) or trauma in brackish waters and skin lesions. Patients most commonly present with one of three clinical syndromes: primary septicemia, wound infection, or gastroenteritis. Treatment includes aggressive wound debridement, antibiotic therapy, and supportive care. Rapidly diagnosing and promptly initiating therapy are critical because V vulnificus infection is rapidly progressive and mortality approaches 100% if septic shock occurs.

Evidence for insertion sequence-mediated spread of the thermostable direct hemolysin gene among Vibrio species

The tdh gene of Vibrio parahaemolyticus which encodes the thermostable direct hemolysin has been found in some strains of other Vibrio species. Analysis of seven tdh genes cloned from V. parahaemolyticus, Vibrio mimicus, and non-O1 Vibrio cholerae revealed that all tdh genes were flanked by insertion sequence-like elements (collectively named ISVs) or related sequences derived from genetic rearrangement of ISVs. The ISVs possessed 18-bp terminal inverted repeats highly homologous to those of IS903 (2- to 4-bp mismatch) and were 881 to 1,058 bp long with less than 33.6% sequence divergence. These features and nucleotide sequence similarities among ISVs and IS903 (overall homologies between ISVs and IS903, ca. 50%) strongly suggest that they were derived from a common ancestral sequence. A family of ISVs were widely distributed in Vibrio species, often regardless of the possession of the tdh genes, and one to several copies of the ISVs per organism were detected. A strain of V. mimicus possessed two copies of the ISVs flanking the tdh gene and three copies unrelated to the tdh gene. However, the transposition activity of the ISVs could not be demonstrated, probably because they had suffered from base changes and insertions and deletions within the transposase gene. The possible mode of ISV-mediated spread of the tdh gene is discussed from an evolutionary standpoint.

Cholera enterotoxin production in Vibrio cholerae O1 strains isolated from the environment and from humans in Japan

Vibrio cholerae O1 strains isolated from various sources in Japan over the years 1977 through 1987 were examined to confirm the presence or absence of the cholera enterotoxin (CT) gene and production of CT and to determine the kappa-phage type. The CT gene was detected in none of 225 isolates from natural waters but was present in all of the 10 isolates from environmental waters implicated in domestic cholera cases, in 64 strains (26.6%) of the 241 isolates from imported seafoods, in 43 strains (95.6%) of the 45 isolates from domestic cholera cases, and in 119 strains (93.7%) of the 127 isolates from imported cholera cases. The results suggest that the CT gene-positive strains of V. cholerae O1 have been imported into Japan through seafoods and/or by travelers. Sporadic cholera cases have resulted in contamination of the surrounding environment, but the CT gene-positive strains may not have persisted in natural waters to serve as a reservoir for epidemic cholera. The commercially available VET-RPLA kit (a latex agglutination kit for immunological detection of CT) detected production of CT in all of the CT gene-positive strains, indicating that there was no silent CT gene in the test strains. There was a strong correlation between the kappa-phage type and the presence or absence of the CT gene, suggesting a significant clonal difference between CT gene-positive and -negative strains. Five CT gene-negative strains isolated from imported cholera cases (travelers with mild diarrhea) induced a considerable amount of fluid accumulation in rabbit and/or suckling mouse intestines, indicating production of an enterotoxic factor(s) other than CT.(ABSTRACT TRUNCATED AT 250 WORDS)

Toxigenic Vibrio cholerae non-O:1 isolated from a goat in The Netherlands

A case of enterotoxicosis in a goat at necropsy is described. The animal had died without clinical signs. Toxigenic Vibrio cholerae non-O:1 was isolated from the intestines. This species has not been reported earlier from healthy or diseased farm animals, such as goats, in the Netherlands.

Gas-liquid chromatographic analysis of cellular fatty acid methyl esters in Aeromonas species

The cellular fatty acids of 39 strains belonging to the genus Aeromonas (Aeromonas hydrophila, Aeromonas caviae, Aeromonas sobria, Aeromonas media, Aeromonas schubertii, Aeromonas veronii) were determined by high resolution gas-liquid chromatography. The fatty acid profiles were characterized by major amounts (60% or more) of one saturated (hexadecanoic acid = 16:0) and two unsaturated (hexadecenoic acid = 16:1 and octadecenoic acid = 18:1) acids. While the majority of the strains of the six species exhibited, qualitatively, very similar fatty acid compositions, only minor and inconsistent differences could be observed which would be useful for a distinction of the different taxons. The following fatty acids were qualitatively identified: 12:0, i-13:0, 14:0, 3-OH 13:0, i-15:0, 15:0, 2-OH 14:0, 3-OH 14:0, i-16:0, 16:1, 16:0, i-17:1, i-17:0, a-17:0, 17:0 cyclopropane, 17:1, 17:0, 18:1 (3 isomers), 18:0 and i-20:0. Excellent congruence was found in reproducibility studies. Fatty acid analyses show a great homogeneity within the group and the technique does not appear to be the ideal method in distinguishing between Aeromonas species.

Characterization of a new thermostable direct haemolysin produced by a Kanagawa-phenomenon-negative clinical isolate of Vibrio parahaemolyticus

The production of two haemolysins, thermostable direct haemolysin (Vp-TDH) and a Vp-TDH-related haemolysin (Vp-TRH), by clinical isolates of Vibrio parahaemolyticus has previously been reported. Here we describe a third type of haemolysin (named Vp-TDH/I), which is produced by a clinical isolate (strain TH012) that is Kanagawa phenomenon negative. Vp-TDH/I was purified by a series of column chromatographies on DEAE-Sephadex A25, hydroxyapatite, Sepharose 4B and Mono Q. By physicochemical, biological and immunological analyses, Vp-TDH/I was demonstrated to be similar, but not identical, to Vp-TDH and Vp-TRH. The gene encoding Vp-TDH/I was cloned and the deduced amino acid sequence of Vp-TDH/I confirmed that Vp-TDH/I has a sequence different from those of previously known Vp-TDH and Vp-TRH. Not only purified Vp-TDH/I but also live cells of the Vp-TDH/I-producing strain induced fluid accumulation in ligated rabbit intestine. We conclude that this clinical isolate produces a new type of Vp-TDH-related haemolysin, which may be involved in the pathogenesis of this organism.

Tryptophan 65 is essential for hemolytic activity of the thermostable direct hemolysin from Vibrio parahaemolyticus

The effect of modification of aromatic and ionizable amino acid residues on the hemolytic activity of a thermostable direct hemolysin from Vibrio parahaemolyticus was examined. Tryptophan 65, one of the two tryptophan residues per subunit, was specifically modified with N-bromosuccinimide, resulting in complete loss of hemolytic activity. However, neither nitration with tetranitromethane of one of the nine tyrosine residues nor Nlm-ethoxyformylation of two of the four histidine residues caused any change in hemolytic activity. The hemolysin was fully active upon amidation of two reactive carboxyl group. On the other hand, acetylation of amino groups and the modification of one of the three arginine residues with 1,2-cyclohexanedione resulted in a partial loss of the hemolytic activity. The results suggest that Trp65 is essential for the hemolytic activity of V. parahaemolyticus hemolysin.

Isolation of Candida albicans and halophilic Vibrio spp. from aquatic birds in Connecticut and Florida

Halophilic vibrios were recovered from feces of six types of aquatic birds (gulls, pelicans, Canada geese, swans, egrets, cormorants) from Connecticut and/or Florida shorelines. Candida albicans was isolated from gulls and Canada geese in Connecticut and from gulls and cormorants in Florida.

Isolation of Vibrio cholerae non-01 from a Somerset farmworker and his tropical fish tank

Vibrio cholerae non-01 is occasionally isolated from wounds. To our knowledge, this is the first such case to be reported from the U.K. It was associated with isolation of a similar organism from a tropical fish tank.

Emergence of a restricted bioserovar of Vibrio parahaemolyticus as the predominant cause of Vibrio-associated gastroenteritis on the West Coast of the United States and Mexico

Examination of 45 human fecal isolates of Vibrio parahaemolyticus revealed the emergence of an unusual bioserovar (O4:K12, urease positive) associated with cases of gastroenteritis which appear to be domestically acquired on the West Coast of the United States and Mexico.

Occurrence and characteristics of agglutination of Vibrio cholerae by serum from the eastern oyster, Crassostrea virginica

Cell-free hemolymph (serum) of the eastern oyster, Crassostrea virginica, agglutinated Vibrio cholerae, including all O1 serovars and biovars. Seventy-nine other strains of bacteria, including 14 genera and 26 species, were not agglutinated. The A, B, and C factors of O1 antigen were not involved in agglutination. Bacterial agglutinating (BA) activity was demonstrated for oysters inhabiting different environments of the U.S. Atlantic and Gulf coasts. Oyster serum BA titers showed high individual variation. The serum component(s) involved in BA was inhibited by 80 degrees C heat, pronase, EDTA, mucin, and fetuin treatments. N-Acetylneuraminic acid (10 mg/ml) weakly inhibited BA activity. Ligands of V. cholerae were sensitive to neuraminidase and resistant to 80 degrees C and pronase. High salinities (24 and 30%) enhanced BA. Cross-adsorption tests with V. cholerae and human O+ erythrocytes indicated that BA and hemagglutinating activities may involve different serum components. These results imply that the ecology of V. cholerae in C. virginica is influenced by agglutinating activity of oyster serum.

Purification and characterization of a protease produced by Vibrio cholerae non-O1 and comparison with a protease of V. cholerae O1

A protease produced by a clinical isolate of Vibrio cholerae non-O1 was purified to apparent homogeneity by ammonium sulfate fractionation and successive column chromatography on DEAE-Sephadex A25, Sephadex G100, Mono Q, and Phenyl Superose. Like the hemagglutinin-protease of V. cholerae O1, the purified protease had both hemagglutinating and proteolytic activities. The protease was heat labile, and in contrast to crude preparations, no Arrhenius effect was observed with the purified protein. Immunological analyses indicated that the proteases (or hemagglutinins) derived from V. cholerae O1 and non-O1 are identical.

Production of monoclonal antibodies against thermostable direct hemolysin of Vibrio parahaemolyticus and application of the antibodies for enzyme-linked immunosorbent assay

A total nine hybridoma cell lines that produced monoclonal antibodies against thermostable direct hemolysin (Vp-TDH), a possible pathogenic toxin, of Kanagawa phenomenon-positive Vibrio parahaemolyticus was isolated and characterized. These monoclonal antibodies (mAbs) were divided into a minimum of five different specificity groups, including mAbs specific to Vp-TDH and common to Vp-TDH and Vp-TRH, a Vp-TDH-related hemolysin produced by Kanagawa phenomenon-negative V. parahaemolyticus. An enzyme-linked immunosorbent assay (ELISA) using mAb-1-D, a mAb specific for Vp-TDH, was developed for specific detection of Vp-TDH. On the other hand, the ELISA using mAb-9-D, and mAb common to both Vp-TDH and Vp-TRH, could be used for detection of both Vp-TDH and Vp-TRH. Thus, by combining these two ELISAs differential detection of Vp-TDH and Vp-TRH can be performed. Hence, the two ELISAs were applied for various strains of V. parahaemolyticus and it was found that most Kanagawa phenomenon-positive and -negative clinical isolates produced Vp-TDH and Vp-TRH, respectively, but all environmental strains, that were Kanagawa phenomenon-negative, produced neither toxin.

The human pathogenic vibrios--a public health update with environmental perspectives

Pathogenic Vibrio species are naturally-occurring bacteria in freshwater and saline aquatic environments. Counts of free-living bacteria in water are generally less than required to induce disease. Increases in number of organisms towards an infective dose can occur as water temperatures rise seasonally followed by growth and concentration of bacteria on higher animals, such as chitinous plankton, or accumulation by shellfish and seafood. Pathogenic Vibrio species must elaborate a series of virulence factors to elicit disease in humans. Activities which predispose diarrhoeal and extraintestinal infections include ingestion of seafood and shellfish and occupational or recreational exposure to natural aquatic environments, especially those above 20 degrees C. Travel to areas endemic for diseases due to pathogenic Vibrio species may be associated with infections. Host risk factors strongly associated with infections are lack of gastric acid and liver disorders. Involvement of pathogenic Vibrio species in cases of diarrhoea should be suspected especially if infection is associated with ingestion of seafood or shellfish, raw or undercooked, in the previous 72 h. Vibrio species should be suspected in any acute infection associated with wounds sustained or exposed in the marine or estuarine environment. Laboratories serving coastal areas where infection due to pathogenic Vibrio species are most likely to occur should consider routine use of TCBS agar and other detection regimens for culture of Vibrio species from faeces, blood and samples from wound and ear infections.