Prevalence, molecular characterization and antimicrobial resistance of E. coli isolates from diarrhoeic lambs in Andhra Pradesh

Abstract

A study was carried out on isolation, molecular characterization and antimicrobial resistance of E. coli isolated from faecal samples of diarrhoeic lambs with the aim to detect antimicrobial resistance in E. coli associated diarrhoeic lambs of this geographic region. A total of 212 faecal samples from diarrhoeic lambs of 1-7, 8-30, 31-60 and 61-90 days age groups were collected from Vizianagaram, West Godavari, Krishna, districts of Andhra Pradesh of which 170 E. coli were isolated with a prevalence rate of 80.18%. After cultural and biochemical confirmation of E. coli the isolates were further confirmed by molecular characterization. The antimicrobial resistance of isolates was tested by disk diffusion method. Among the three districts, higher prevalence of E. coli in diarrhoeic lambs was recorded in West Godavari district (86.41%), while lower (72.83%) prevalence was found in Krishna district. Irrespective of the districts, higher prevalence of E. coli was observed in 1-7 day-old diarrhoeic lambs (84%), while lower prevalence was detected in 61-90 day-old age group (72.72%). This study detected highest antibiotic resistance in E. coli isolates against colistin (98.82%) and sulphamethizole (89.41%), while enrofloxacin (5.88%), gentamicin (5.33%) and chloramphenicol (1.17%) were effective. This study provided baseline data on prevalence of E. coli associated diarrhoea and antimicrobial resistance against commonly used antimicrobials in sheep.