Seasonality and antimicrobial resistance pattern of Vibrio cholerae in a tertiary care hospital of North India

We retrospectively analysed the seasonal distribution of cholera and the antimicrobial resistance pattern of Vibrio cholerae isolates over a 5-year period from January 1998 to December 2002. Of 3213 stool specimens processed from 3213 patients with acute watery diarrhoea during this period, 431 samples (13.4%) were found positive for V. cholerae. There were 423 V. cholerae O1 biotype E1 Tor, 2 V. cholerae O139 and six isolates of non-O1 non-O139. The highest number of cholera cases occurred in May-June followed by July-August. Cases started appearing in April for all years except in the year 2002 when three cases occurred in the first week of March. A large number (90.25% strains) were resistant to at least one antibiotic.