Prevalence and virulence gene profiles of Shiga toxin-producing Escherichia coli and enteropathogenic Escherichia coli from diarrhoeic and healthy lambs in India

This communication describes the prevalence and virulence attributes of Shiga toxin-producing Escherichia coli (STEC) and enteropathogenic E. coli (EPEC) isolates in lambs with and without diarrhoea in Kashmir, India. One hundred twenty and 164 E. coli isolates belonging to 56 different ‘O’ serogroups were isolated from 101 diarrhoeic and 135 healthy lambs, respectively. All the 284 isolates were screened for presence of stx1, stx2, eae and ehxA genes using multiplex polymerase chain reaction (m-PCR). Forty four (36.67%) isolates from lambs with diarrhoea carried at least one virulence gene studied. Twenty one (17.5%) and 15 (12.5%) isolates from diarrhoeic lambs were STEC and EPEC, respectively. Thirty (18.3%) isolates from healthy lambs possessed at least one virulence gene studied. Fourteen (8.53%) and 16 (9.75%) isolates from healthy lambs were detected as STEC and EPEC, respectively. Sixteen (45.71%) of 35 STEC isolates from both diarrhoeic and healthy lambs, carried both stx1 and stx2 genes, 15 (42.85%) had stx1 alone and four (11.42%) had stx2 gene alone. Statistically the difference between prevalence of STEC in diarrhoeic and healthy lambs was significant but that of EPEC was insignificant. One (2.85%) and 28 (80%) of STEC isolates possessed eae and ehxA genes, respectively. The high percentage of STEC and EPEC prevalent in diarrhoeic and healthy lambs may serve as source of infection to humans. STEC seem to be associated with diarrhoea in lambs.