Prevalence of shiga toxin-producing Escherichia coli in buffaloes on smallholdings in coastal area in Bangladesh

Shiga toxin-producing Escherichia coli (STEC) is an important causal agent of food borne diseases. Although the presence of STEC has been reported in cattle, goat, and sheep in previous studies in Bangladesh, there is seemingly no information on sorbitol non-fermenting STEC (SN-F STEC) carriage in buffalo. We aimed to assess the prevalence of SN-F STEC and to identify common virulence genes in SN-F STEC strains from apparently healthy buffaloes on smallholdings in coastal area in Bangladesh. Total 308 buffaloes on smallholdings in Patenga and Anwara Upazila, Chattogram division, Bangladesh were randomly sampled by collecting a swab from the recto-anal junction of each animal. SN-F E. coli was identified based on colony morphology (colorless) yielded on Cefixime tellurite sorbitol MacConkey (CT-SMAC) agar. SN-F E. coli was detected in 33 [10.7%, 95% Confidence Interval (CI): 7.7-14.7)] of the animals sampled. Among them, 12 (3.9%, 95% CI: 2.2-6.8) were STEC positive. These isolates were characterized for the presence of stx (stx1 and stx2) and common virulence genes, eae and hlyA by the Polymerase Chain Reaction (PCR). Fourteen isolates exposed only one gene, five isolates harbored two genes and two isolates carried three genes. Healthy buffaloes carry STEC, though its prevalence is comparatively lower than from cattle could pose a risk to public health reared on smallholdings.