Altered El Tor Vibrio cholerae O1 Caused Outbreak of Cholera in the Southern Part of Odisha, India during 2011

Outbreak of cholera reported during July to October, 2011 from the Mohana block of Gajapati district of Odisha was investigated. Sixty rectal swabs collected from severe diarrhoea patients and 64 water samples were bacteriologically analyzed for the isolation of bacterial pathogens, antibiogram profile and detection of various toxic genes. Bacteriological analysis of rectal swabs and water samples detected Vcholerae O1 Ogawa biotype El Tor. The V. cholerae strains were resistant to streptomycin, erythromycin, ampicillin, furazolidone, co-trimoxazole nalidixic acid and chloramphenicol. The multiplex PCR assay on V. cholerae strains indicated the presence of ctxA and tcpA genes showing biotype El Tor; whereas mismatch amplification of mutation assay (MAMA) PCR assay on clinical and water isolates of V. cholerae revealed that they were El Tor variant carrying ctxB gene of the classical strain. This clearly indicates the homology of clinical and environmental isolates of Vcholerae isolated during the outbreak period. Early reporting enabled the state government to implement control measures to check the spread of the disease. The present findings clearly gives an warning that the altered El Tor Vcholerae O1 strains with classical traits spread in the tribal areas causing cholera outbreak that may repeat in future which needs close monitoring.