Cytotoxicity of non O1, non O139 Vibrios isolated from fresh water bodies in Vellore, south India.

The samples of plankton, soil sediment and water from a pond, a lake and a moat respectively in and around Vellore were studied for environmental vibrios. Vibrios were isolated from all these specimens after enrichment in alkaline peptone water and subculture on selective media. Non O1, non O139 Vibrio cholerae, Aeromonas spp. and Plesiomonas spp. were isolated. There were no isolates of V. cholerae serogroup O1 and O139. Representative strains of non O1 and non O139 V. cholerae from environmental sources were tested for toxin production in Chinese hamster ovary (CHO) and Vero cell monolayer in microtitre plates. Thirty-three (91.7%) of the 36 strains tested demonstrated cytopathic effect (CPE) in both cell lines indicating their toxigenicity. PCR done on representative strains of non O1 and non O139 V. cholerae showed that none of the strains were positive for ctx A, tcp A-E and tcp C genes. These results indicate that these non agglutinating environmental vibrios produced cytotoxins other than the cholera toxin.

Frecuencia de aislamiento de Vibrio cholerae en aguas y en plancton de la cuenca inferior del río Salado (Santa Fe, Argentina) / Frequency of isolation of Vibrio cholerae from waters and plankton in the lower Salado River Basin (Santa Fe Province, Argentina)

Durante enero 1993 - diciembre 1996 se recolectaron 85 muestras de agua y 40 de plancton en la cuenca inferior del río Salado. En el 69,4 o/o de las muestras de agua en el 75 o/o de las muestras de plancton se detectó Vibrio cholerae. Ninguna de las cepas de V. cholerae aisladas pertenecieron a los subgrupos O1 y O139. No se comprobó estacionalidad en la frecuencia de los aislamientos de V. cholerae aplicando la prueba de comparación de proporciones múltiples (p>0,05). Se registraron diferencias significativas (p<0,05) entre la frecuencia de aislamiento de V. cholerae en el río Salado (85 muestras, 69,4 o/o) y la hallada en ambientes del río Paraná (16 muestras, 25 o/o) y en efluentes municipales (18 muestras, 33,3 o/o)