Detection of Shiga toxigenic (STEC) and enteropathogenic (EPEC) Escherichia coli in dairy buffalo

Enteropathogenic (EPEC) and Shiga toxigenic (STEC) Escherichia coli are among the bacteria most associated with enteric diseases in man. The aims of this study were to determine the prevalence of STEC and EPEC in dairy buffalo and then characterize these isolates genetically. To determine the prevalence of these bacteria, samples were collected from the feces and milk of buffaloes. In total, 256 samples were collected in 3 samplings, of which 76 samples tested positive for either the stxl, stx2 or eae genes or a combination thereof. From the positive samples, 22 STEC and 11 atypical EPEC (aEPEC) isolates were obtained. The isolates showed 23 different genetic profiles. No profile was very frequent in STEC isolates. On the other hand, the profile eae+, ehxA+, iha+, efal+, toxB+, paa+, lpfA(0113)+ was found in 45% of the aEPEC isolates. In addition to stxl, stx2 and eae, the genes ehxA, efat saa, lpfA(0113), IPfA(0157/0I-141), IPfA(0157/0I-154), toxB and iha were present in the isolates. Serogroup 026 was found in 26% of the aEPEC. Other serogroups detected include 087, 0145, 0176 and 0179. The isolates were sensitive to almost all drugs tested and some isolates shared the same fingerprint patterns by enterobacterial repetitive intergenic consensus sequence-PCR (ERIC-PCR). The results suggest that, besides major reservoirs of STEC, buffaloes are also aEPEC reservoirs. The detection of a serogroup (026), and putative virulence genes (efal ehxA, paa and lpfA(0113)), previously associated with aEPEC isolated from humans with diarrhea in aEPEC from buffaloes should be studied further. (c) 2014 Elsevier B.V. All rights reserved.