Investigation of diarrhoeic faecal samples for enterotoxigenic, Shiga toxin-producing and typical or atypical enteropathogenic Escherichia coli in Kashmir, India

Three hundred and twenty-six Escherichia coli isolates recovered from 326 human faecal specimens from sporadic cases of diarrhoea in Kashmir valley, India, were investigated for the presence of stx(1), stx(2), eaeA, hlyA and lt virulence genes. None of the samples was positive for stx genes or Shiga toxins by PCR or enzyme-linked immunosorbent assay. Twenty-three E. coli isolates showed the presence of the eaeA gene, whereas three isolates harboured the lt gene. Enteropathogenic E. coli (EPEC) belonged to 10 different serogroups. Out of 23 EPEC isolates, the majority (78.26%) were atypical while five (21.73%) were typical. Only one of the typical EPEC harboured the EAF plasmid. Subtyping of the eaeA gene showed the presence of eaeA-alpha(1), eaeA-beta, eaeA-xi and eaeA-eta in one, two, four and two isolates, respectively. None of the E. coli isolates possessed eaeA-delta, eaeA-epsilon and eaeA-zeta. This study further upholds the opinion that Shiga toxin-producing E. coli do not pose a major threat to human health in India and eaeA-alpha(1), eaeA-beta, eaeA-xi and eaeA-eta could be common EPEC subtypes prevalent in humans with diarrhoea in India. The present study appears to be the first report of subtype analysis of the eaeA gene from India and also records the isolation of EPEC with the eaeA-xi gene from humans.