Escherichia coli in diarrhoeic lambs: Prevalence, virulence and antibiotic resistance

The present study aimed to detect the prevalence, virulence and antimicrobial resistance genes profile of Escherichia coli isolated from diarrhoeic lambs. A total of 61 faecal samples were collected from diarrhoeic lambs. The presence of various virulence and antimicrobial resistance genes in E. coli isolates was determined by the use of PCR. In total, 46 E. coli isolates were recovered from 61 rectal swabs of diarrhoeic lambs. Out of these 46 isolates, PCR showed that seven isolates (15.22%) carried the stx1 or stx2 gene and were found positive for Shiga-toxin-producing E. coli (STEC). Four isolates (8.70%) were found to be Enteropathogenic E. coli (EPEC) and all these EPEC isolates were atypical EPEC pathotypes. STEC and intimin-positive isolates were recovered only from one isolate, hence, out of 46 isolates, only one isolate (2.17%) was confirmed as Enterohaemorrhagic E. coli. The lt and st genes were not detected in any of the E. coli isolates recovered from field samples. Therefore, all the isolates were confirmed as non-Enterotoxigenic E. coli. Further, thirty-five isolates (76.09%) were found to be Entero-aggregative E. coli pathotypes. All the E. coli isolates were also tested for antimicrobial resistance against 15 different antibiotics. All the E. coli isolates were found to be resistant to penicillin-G, cephalothins, and azithromycin and the majority of isolates of E. coli were sensitive to chloramphenicol, ofloxacin, and sulfafurazole. Two antibiotic resistance genes i.e. tetA and blaTEM were detected in 10.87% (n=5/46) and 28.26% (n=13/46) of E. coli isolates, respectively.