Multidrug-resistant Vibrio cholerae O1 in Belgaum, south India

An outbreak of acute diarrhoea occurred in the Belgundi area (population 3896) of Belgaum Taluka (population 815 581) in Karnataka, South India, in June 2010. An estimated 16.22% of people were affected and 0.16% deaths were reported. Vibrio cholerae O1 El Tor was isolated from 18 of the 147 stool samples cultured. Seven out of eight drinking water samples collected from different sources were found to be grossly contaminated with faecal coliforms. All isolates were multidrug resistant, with some showing resistance to quinolones, gentamicin and cephalosporins in addition to co-trimoxazole and tetracycline, the drugs that were being used by the state health authorities for empirical treatment. Two serotypes and at least eight genotypes of V. cholerae were observed among the isolates. Cholera was confirmed as one, if not the only, cause of the outbreak, which, to our belief, is the first report of cholera from this region. It might have occurred due to a 'flare up' in the number of endemic strains triggered by shortage of portable water, onset of monsoon rains and breakdown of sanitation systems, rather than being a de novo outbreak arising out of new exogenous infectious sources. A change in the empirical treatment, coupled with chlorination, improvement in sanitation measures and extensive Information Education Communication activities, resulted in decline of the outbreak and prevention of further deaths.