SEROTYPES OF VIBRIO PARAHAEMOLYTICUS FROM CLINICAL AND ENVIRONMENTAL SOURCES IN TOGO (WEST AFRICA)

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.

Serotypes of Vibrio parahaemolyticus isolates from hydrobiologically dissimilar aquatic environments

Serological analysis of the O and K antigens was performed on 324 isolates of Vibrio parahaemolyticus obtained from three hydrobiologically dissimilar aquatic environments. Only 50.9% of the strains could be serotyped. The largest number of untypable strains and the lowest serological diversity were observed from the freshwater collection. Three serotypes, O2:K28, O5:K17, and O2:K3, dominated among all biotopes. There appears to be some distinction between serotypes of environmental and clinical origins.

An evaluation of the efficiency of enrichment media in the isolation process for Vibrio parahaemolyticus

An evaluation of the efficiency of seven enrichment media for Vibrio parahaemolyticus was effected, by means of material collected from the corporeal surface of 82 marine fish caught off the Brazilian coast. On the whole, 45 fish proved positive, from which 71 strains were taken. Among the culture media analyzed the best results were obtained with the new enrichment media represented by two of the nutrient broth (Difco) pH 8.3; one supplemented with 2 g % of NaCl and 500 mg % eosin Y, and another supplemented with 125 mg % metachrome yellow II RD. The combination of enrichment media plus selective-indicator media demonstrated the superiority of the binary association of alcaline broth eosin Y to TCBS agar, both in the number of isolations and serotypes detected.

Kanagawa phenomenon and serotypic pattern of Vibrio parahaemolyticus strains isolated from various sources in Calcutta

A total of 135 strains of Vibrio parahaemolyticus isolated during the period 1976-77 from human gastroenteritis cases and various categories of environmental sources, e.g., crustaceans, fish and different water samples (pond, stored, open well and tap water) were tested for their Kanagawa phenomenon and serotypic pattern. Amongst the 80 human isolates tested, 69 strains (86.3%) were Kanagawa phenomenon positive, and 60 strains (75.0%) were serologically typable--the dominant serotype being 05:K15. Of the 25 isolates from various water sources 10(40.0%) were Kanagawa phenomenon positive, and 17(68.0%) were serologically typable and 4 (23.5%) of them belonged to serotype 05:K15. All the 30 strains isolated from crustaceans and fish were Kanagawa phenomenon negative and 22 (73.3%) of them were serologically typable, belonging to heterogeneous serotypes. The results of this study also indicate the possible role of water in the transmission of V. parahaemolyticus infection in Calcutta slums.

Butandioldehydrogenase in Vibrio parahaemolyticus

396 strains of V. parahaemolyticus, 345 originating from Togo and 51 from Japan, were submitted to the study of butandiol dehydrogenase (BDH). It was found that 52.3% of the strains were BDH-positive and 44.2% BDH-negative. An intermediate group characterized by weak reactions amounted to 3.5% of the strains. The distribution of this enzyme parallels to a certain degree the results of serotyping. Positive reactions have been found in all or most strains belonging to serotypes 03K29, O4K8, 04K12, 04K55, 05K15, and 012K19, whereas strains of serotypes 03K5 and 04K10 gave negative reactions. In serotype 05K17 both properties were found in nearly equal proportions. The test of BDH, which can supplement serotyping in characterizing strains of V. parahaemolyticus, can be applied as an aid to epidemiological studies.