Changing patterns of Vibrio cholerae isolation over three consecutive cholera seasons (1992-1994) in east Delhi

The emergence of new strains of Vibrio Cholerae has added a new dimension to the variability in pathogenicity and potential virulence of the organisms precipitating diarrhoeal diseases. Considering the shifting patterns of V. cholerae 01 there is a continuous need to monitor the strain characteristics. In this study total 541 stool specimens of acute secretory diarrhoea were investigated between May 1992 and November 1994 for strains of Vibrio Cholerae and anti-microbial susceptibility testing of all the confirmed V. Cholerae strains. In 1992, 50 of the 125 strains (40%) were positive for V. cholerae 01 predominantly biotype El Tor serotype ogawa, and 10 (80%) of non 01 type, with most strains susceptible to tetracycline (100%), chloramphenicol (98%) and Cotrimoxazole (98%), but all resistant to polymyxin B and furazolidine. In 1993, 44 (43.6%) of the 010 strains were positive for V. cholerae 0139 and the rest V. cholerae 01. In 1994, another sero group of V. cholerae 010 emerged, with 42 (13.3%) being positive. Isolates did not agglutinate with any of these antisera and have been labelled as 'other than non-01 vibrio cholerae'.