The annual cycle ofVibrio Parahaemolyticus in chesapeake bay

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.

Occurrence and distribution of Vibrio spp., Listonella spp., and Clostridium botulinum in the Seto Inland Sea of Japan

The distribution of Vibrio species in samples of surface water, bottom water (water 2 m above the sediment), and sediment from the Seto Inland Sea was studied. A simple technique using a membrane filter and short preenrichment in alkaline peptone water was developed to resuscitate the injured cells, followed by plating them onto TCBS agar. In addition, a survey was conducted to determine the incidence of Clostridium botulinum in sediment samples. Large populations of heterotrophs were found in surface water, whereas large numbers of total vibrios were found in bottom water. In samples from various water sampling regions, high counts of all bacterial populations were found in the inner regions having little exchange of seawater when compared with those of the open region of the inland sea. In the identification of 463 isolates, 23 Vibrio spp. and 2 Listonella spp. were observed. V. harveyi was prevalent among the members of the Vibrio genus. Vibrio species were categorized into six groups; an estimated 20% of these species were in the so-called "pathogenic to humans" group. In addition, a significant proportion of this group was hemolytic and found in the Bisan Seto region. V. vulnificus, V. fluvialis, and V. cholerae non-O1 predominated in the constricted area of the inland sea, which is eutrophic as a result of riverine influence. It was concluded that salinity indirectly governs the distribution of total vibrios and analysis of variance revealed that all bacterial populations were distributed homogeneously and the variance values were found to be significant in some water sampling regions.(ABSTRACT TRUNCATED AT 250 WORDS)

[Species of the genus Vibrio associated with marine products from Arachon Bay]

The distribution of Vibrio species in water and seafood collected from Arcachon Bay (located in the southwest of France) was studied. All invertebrate animals collected were associated with one or more Vibrio species. Eighty strains corresponding to 14 species were precisely identified. The identification of strains with V. parahaemolyticus was checked by DNA/DNA hybridization. The most frequently recovered species were V. alginolyticus, V. parahaemolyticus (non-haemolytic strains), V. harveyi and V. metschnikovii. The three V. cholerae non-O1 strains isolated from water and crab did not produce immunologically detectable cholera toxin and had no DNA fragment hybridizing with a cholera-toxin-gene-specific probe. It is suggested that the sanitary surveillance of seafood in France should include the precise characterization of potentially pathogenic Vibrio species.

Ecology ofVibrio cholerae in the freshwater environs of Calcutta, India

Seasonal incidence ofVibrio cholerae was monitored for a year in a man-made freshwater lake, an open sewage canal, and a pond composed of rainwater accumulations, located in Calcutta.V. cholerae was found in all sites. It exhibited a distinct bimodal seasonal cycle in the lake with a primary peak in August-September and a secondary peak in May-June. Correlation with environmental parameters revealed that temperature and, to a certain extent, pH were the important factors governing the densities ofV. cholerae. In the lake, sediment samples harbored high densities ofV. cholerae immediately after months when peak counts were observed in plankton, suggesting a cycle of cells between sediment and water. At the other sampling areas, no defined seasonality was observed. Instead, high counts ofV. cholerae were observed at these severely polluted sites throughout the study period, including the winter months. All the 15 water samples passed via the ligated loop of rabbits yielded pure cultures ofV. cholerae, indicating that the rabbit intestine selects outV. cholerae from a mixed flora. Uniformly high isolation rates ofV. cholerae were observed from brackish water and freshwater species of export quality prawns.V. cholerae was found to be abundant and was represented by 32 individual Louisiana State University (LSU) serovars, including two new serovars. The 01 serovar could not be isolated from any of the samples examined in this study. It was concluded thatV. cholerae non-01 is common in the freshwater environs of Calcutta.

Survival of Vibrio parahaemolyticus in cold smoked fish

Fresh samples of mullet (Mugil cephalus) and oil sardines (Sardinella longiceps) obtained from a fish market were subjected to cold smoking. Some of the samples harboured low levels of Vibrio parahaemolyticus. After cold smoking, however, many samples showed relatively high levels of V. parahaemolyticus suggesting that a small population of naturally occurring organisms could multiply to significant levels during the process of cold smoking or during subsequent storage at room temperature. Nevertheless, smoke components were observed to exert an inhibitory effect on V. parahaemolyticus in broth. Salt concentration 1% appeared to increase the sensitivity of V. parahaemolyticus to smoke components.

Survival of Kanagawa-positive strains of Vibrio parahaemolyticus in a brackish-water area

Vibrio parahaemolyticus was observed to overwinter in sediments and to be present in considerable numbers in sediments and Clithon retropictus (gastropod mollusc) during summer months at a brackish-water area along Hashizu Creek in Japan. The highest level of the organisms was 9.3 X 10(6) and 2.3 X 10(7)/100 g in sediments and C. retropictus respectively. Production of Kanagawa haemolysin was detected in approximately 12% and 20% of strains isolated from sediments and C. retropictus respectively at two stations in Hashizu Creek but were not detected at the other three stations. Two haemolysin-producing strains were isolated from water samples but none were isolated from Corbicula japonica (bivalve mollusc). These findings suggest that haemolysin producers are preserved principally in sediments and some shellfish in the brackish-water areas with restricted salinity conditions.

Statistical evaluation of a quality control method for isolation of pathogenic Vibrio species on selected thiosulfate-citrate-bile salts-sucrose agars

The recovery of Vibrio cholerae, Vibrio fluvialis, Vibrio parahaemolyticus, and Vibrio vulnificus, employing eight strains of each species, was studied by using four brands of thiosulfate-citrate-bile salts-sucrose (TCBS) agar prepared according to manufacturers' instructions and following a standardized procedure. A standardized broth inoculum of each strain was placed on duplicate plates of each brand of TCBS agar and also on tryptic soy agar (Difco Laboratories) containing 1% (wt/vol) NaCl, the latter serving as the control. Plates were inoculated in a sequence designed to compensate for bias associated with multiplication of the bacteria during the inoculation procedure. Colony counts and quality of growth were recorded after incubation for 18 h at 35 degrees C. The comparison procedure was repeated four times at weekly intervals. Data were analyzed by using an analysis of variance model. The recovery and quality of growth of each species varied significantly on the different brands of TCBS agar. Significant variability was also identified for some components of the inoculation procedure. Modifications of the inoculation procedure are suggested to minimize sources of variance. A simplified statistical procedure, based on the t test, is described for media quality control for laboratories routinely isolating pathogenic Vibrio spp.

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.

Incidence of marine bdellovibrios lytic against Vibrio parahaemolyticus in Chesapeake Bay

The incidence of marine bdellovibrios at selected sampling sites in the Chesapeake Bay during the months of June 1978 and 1979 was studied. Bdellovibrios were isolated from eight of nine sampling stations in the bay. Higher numbers than previously reported with sea or ocean water were recovered in the midregion of the bay.