Shiga toxin-producing Escherichia coli O26 strains in bovine feces in East-Azarbaijan, Iran

Abstract

Shiga toxin-producing Escherichia coli (STEC) strains are a diverse group of organisms associated with severe gastrointestinal and systemic disease in human. Among non-O157 STEC family, E. coli O26 strains are the common serogroup causing disease such as HUS in human. Cattle are thought to be the main source of this microorganism. We collected 211 samples of bovine feces from different area in East-Azarbaijan province and cultured them in Rhamnose-MacConkey agar supplemented with Cefixime and potassium-tellurite, (CT-RMAC agar). Colorless colonies in CT-RMAC agar medium confirmed by multiplex PCR assay using primer specific for genes encoding biosynthesis of the O antigens (O-antigen flippase and O-antigen polymerase) and shiga toxins (stx 1 and stx 2). There were colorless colonies in CT-RMAC agar medium of 18 samples (8.53 %) that 17 samples (8.05 %) of them were positive for the presence of the respective genes. Relatively high number of STEC O26 positive cattle found in our region can be a potential vehicle for transmission of this pathogen directly or indirectly (from food) to human.