A qPCR Assay to Monitor and Detect Shiga- Toxin Producing E. coli in Raw Materials and Food in the Egyptian Market

Abstract

Shiga toxin producing Escherichia coli (STEC) are dangerous foodborne pathogens which represent a severe public health issue worldwide. Raw foods are considered as important sources for STEC infection in human. In the current study, STEC contamination level was determined in 39 raw foods and materials (chicken, beef, milk and water) collected from farms,

butchers, and retail markets in different localities of the Greater Cairo using Real-Time PCR (RT- PCR). Moreover, the virulence genes of the isolated strains were characterized. STEC was

detected in three samples which represent about 8% of the tested samples, wherein they were all beef samples. Two samples were positive for the eaeA (intimin) and stx2 gene, however; the third sample was eaeA-negative and stx2-positive. The stx2 gene of STEC bacteria was the most prevalent subtype identified in beef samples. Among the three positive samples, four STEC

strains were isolated; two strains belonged to O157 serogroup and the other two belonged to non- O157 serogroup (O26).