Detection & characterization of Shiga toxin producing Escherichia coli (STEC) & enteropathogenic Escherichia coli (EPEC) in poultry birds with diarrhoea

BACKGROUND & OBJECTIVES: Limited information is available on shiga toxin producing Escherichia coli (STEC) in animals and birds from India. An outbreak of acute diarrhoea in poultry birds at Aizawl, Mizoram was investigated for detection and characterization of STEC and enteropathogenic E. coli (EPEC). METHODS: E. coli was isolated and identified from rectal swabs, intestinal contents, heart blood and spleen of 19 poultry birds that died due to acute diarrhoea during the outbreak. Phenotypic characterization was done by standard bacteriological and biochemical techniques. All the isolates were serotyped based on their somatic antigens. Virulence genes (stx(1), stx(2), eaeA and hlyA) were detected by multiplex PCR assay. RESULTS: A total of 42 E. coli isolates were obtained, of which 24 belonged to 3 serogroups (O64, O89 and O91) and the remaining 18 were untypable (UT). Altogether, 14 (33.33%) isolates carried at least 1 virulence gene, of which 10 (23.81%) and 4 (9.52%) were recorded as STEC and EPEC, respectively. Of the 10 STEC isolates, one carried only stx(2), one carried stx(2) and hlyA, four carried stx(1), stx(2) and hlyA, two carried stx(1), eaeA and hlyA genes and two carried stx(1) and eaeA. Of the four EPEC isolates, two carried eaeA and hlyA, one carried only eaeA gene and 1 carried only hlyA gene. INTERPRETATION & CONCLUSIONS: This is the first report on the involvement of STEC in poultry in India.