Changing epidemiology and antimicrobial resistance pattern of Vibrio cholerae isolates at a tertiary care health laboratory in North India (2011–2015)

Abstract

Background: Vibrio cholerae is a common bacterial enteropathogen causing acute diarrheal disease in the developing world. Marked variations in epidemiology and in in vitro susceptibility of isolates are commonly observed, and emerging and progressive resistance to various classes of antibiotics is frequent. The present research was undertaken to document the epidemiological profile of cholera cases in Delhi and surrounding areas and to monitor the antibiotic resistance patterns of this enteropathogen across the study years. Materials and Methods: The present retrospective analysis was conducted over a 5-year period (2011–2015) at a tertiary care medical center in New Delhi, India. A cumulative 11,570 diarrheic/dysentric fecal samples received in the laboratory were processed for common enteropathogens by standard bacteriological methods. Any suspected V. cholerae colonies were identified by standard biochemical reactions, and serological confirmation was obtained by agglutination using specific antisera. Antimicrobial susceptibility profile of the isolated strains was assessed by Kirby–Bauer's disc diffusion technique and in accordance with the Clinical and Laboratory Standards Institute guidelines. Results: V. cholerae was isolated in 2.4% of the stool samples, with V. cholerae O1 serotype Ogawa being the most prevalent serotype, and a rise in the number of cholera cases was evident during monsoon season each year. While resistance to nalidixic acid and ampicillin was consistently high during the study period, aminoglycoside resistance showed variance and fluctuations across the study years. Further, a significant rise was seen in resistance to ciprofloxacin and cefotaxime. Conclusions: Our findings suggest high levels of antibiotic resistance among the circulating V. cholerae strains in this part of the country, with fluctuations in antibiograms being commonly noted. Therefore, active and continuous community surveillance of changing epidemiology and antimicrobial resistance profile of this enteropathogen is of utmost importance.