Epidemiology, molecular characterization and antimicrobial resistance of Necrotoxigenic Escherichia coli in diarrhoeic calves

A study was carried out to investigate the epidemiology, molecular characterization and antibiotic resistance of Necrotoxigenic E. coli (NTEC) isolated from diarrhoeic calves in Andhra Pradesh (AP) and Telangana States (TS). A total of 129 faecal samples from diarrhoeic buffalo calves of 1 to 90 days were collected from various districts in AP and TS, of which 60 E.coli were isolated. The cnf2 gene was detected by PCR and In vitro antibiotic susceptibility was tested by disk diffusion methods. The prevalence of E.coli associated diarrhea in calves was 46.51% of which 5.0% was due to NTEC based on the presence of cnf2 gene and none of the E.coli isolates possessed cnf1 gene. The NTEC isolates from diarrhoeic calves showed higher antibiotic resistance to tetracyclin and aztreonam (66.67%) and sensitive to ampicillin, cefotaxime, ceftazidime, amoxycillinclavulinicacid, gentamycin, kanamycin, streptomycin, sulfisoxazole, cotrimoxazole, ciprofloxacin, chloramphenicol and imipenem antibiotics. The present study provides baseline data on epidemiology of E.coli associated diarrhoeia, NTEC prevalence and antimicrobial resistance in calves which will help in formulating prophylactic and preventive measures in this geographic region.