Antimicrobial resistance in selected bacterial enteropathogens in north India

The resistance of enteropathogenic bacteria to commonly prescribed antibiotics is increasing both in developing as well as in developed countries. Resistance has emerged even to newer, more potent antimicrobial agents. The present study was therefore undertaken to report the current antibiotic resistance in common bacterial enteropathogens isolated in a tertiary care hospital in north India.

Faecal samples from 1802 patients were cultured for common bacterial enteropathogens and identified by standard methods. Antibiotic susceptibility was done by Stoke's disk diffusion method. The clinical and demographic profile of the patients was noted.

Stool specimens from 119 (88 male, 31 female) patients yielded Shigella, Salmonella, Vibrio cholerae or Aeromonas. Fifty two per cent (62/119) of patients were children and 70 per cent were below the age of 5 yr. Twenty seven patients developed hospital acquired diarrhoea. Among all enteropathogens, Shigella spp. was the commonest followed by non-typhoidal Salmonella (27), V. cholerae O1 El tor serotype Ogawa (19), Aeromonas spp. (14), Salmonella Typhi and S. paratyphi A (2 isolates each). Resistance to antimicrobial agents was common among all pathogens. Among shigellae an overall resistance of 63.6, 58.1 and 16.3 per cent was observed for nalidixic acid, cotrimoxazole and furazolidone respectively. Seven isolates of Shigella were resistant to ciprofloxacin, (18.5%) of non-typhoidal salmonellae were resistant to ciprofloxacin. V. cholerae were generally susceptible to tetracycline (only 1 isolate out of 13 resistant) and other drugs except nalidixic acid (89.5% resistance) and cotrimoxazole (77.8% resistance).

Enteropathogens have developed high level resistance to first line agents used for empiric treatment of diarrhoea. Progressively increasing resistance to ciprofloxacin is a serious cause of concern.