Prevalence, isolation and antibiogram study of pathogenic E. coli from poultry farms in and around Patna

Escherichia coli (E. coli), a member of the Enterobacteriaceae family, is a Gram-negative, rod-shaped, facultatively anaerobic bacterium commonly found in the intestines of birds and animals. Although it is part of the normal gut flora, certain enteropathogenic and toxigenic strains can cause a range of enteric and extra-intestinal infections in poultry. While previous studies have investigated the prevalence, isolation and antibiotic susceptibility profiles of E. coli, its characteristics are known to vary across regions and time periods. This study was undertaken to assess the prevalence of E. coli infections contributing to poultry diseases in and around Patna, with a specific focus on the antimicrobial resistance patterns of isolated strains. A total of 500 birds underwent necropsy, from which 200 suspected cases of colibacillosis on the basis of history and gross lesions were selected for further microbiological analysis and confirmation. Escherichia coli was successfully isolated from 120 of these samples, representing 60.0%. Of these, 113 isolates (56.5%) were biochemically confirmed as E. coli. Infections were more prevalent among younger chickens during the monsoon season. Antimicrobial susceptibility testing was conducted on all biochemically confirmed isolates using the standard disc diffusion method. The results indicated that tetracycline exhibited the highest resistance, followed by ciprofloxacin. Based on the findings, E. coli was identified as a predominant gastrointestinal pathogen in poultry and cephalexin was suggested as an effective treatment option against the prevailing strains.