Detection and virulence gene characterization of Shiga toxigenic E. coli from buffalo meat samples

Shiga-toxigenic Escherichia coli (STEC) are causative agents of bloody diarrhoea, haemorrhagic colitis (HC) and haemolytic uraemic syndrome (HUS). Humans acquire infections primarily through contaminated beef. In India, STEC has not been implicated as a major cause of diarrhoea. The study was carried out to know the prevalence of shiga toxin (ST) producing Escherichia coli (STEC) and virulence genes characterization from buffalo meat samples sold at various retail meat shops at Anand, India. In the present investigation 70 isolates of Escherichia coli isolated from 150 retail market buffalo meat samples, were screened for STEC, using conventional culture methods, serotyping and polymerase chain reaction (PCR). Out of 70 E. coli isolates 11 different ‘O’ serogroups were recorded in 44 isolates. While 19 isolates were untypable and seven were rough isolates. Out of the 70 E. coli tested 56 isolates (80%) were positive for stx genes: of which 51 (72.85%) harboured stx2 genes and 2 isolates (2.85%) were positive for stx1 gene only. Moreover, 3 E. coli isolates (4.28%) harboured both stx1 and stx2. About 66 (94.28%) isolates were positive for eaeA gene. While out of 70 E. coli isolates tested, 3 (4.28%) were found to be positive for rfb O157 gene. Presence of STEC and other virulence factors in buffalo meat samples appeared to be matter of concern and threat to public health.