Detection and Evaluation of Escherichia coli O157:H7 and Shiga-toxin Genes stx1, stx2 in Cattle Meat Samples.

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Background: Screening of transmission routes and routine control of the food for foodborne-pathogens are vital in terms of public health. In this study, we aimed to investigate and evaluate the presence of E. coli O157:H7 strains and toxins in the cattle meat samples collected from different markets and butchers. Methods: We collected 116 raw minced cattle beef samples from the supermarkets and the butcher stores. We used bacterial culture-based conventional isolation methods as recommended by the CDC and FDA determination of STEC in the minced cattle beef samples. Then we used PCR to detect stx genes in sorbitol negative E. coli. This way, we indirectly demonstrated the presence of the stx genes in meat samples. Additionally, we used an agglutination test for the detection of E. coli O157:H7. Results: E. coli O157-suspected isolates were found in 17 (14.6%) out of 116 raw minced meat samples examined with tests. STEC stx toxin gene was found in 14 (12.06%) of the sorbitol-negative E. coli isolates tested with real-time PCR method. There was no statistical difference between samples collected from markets and butchers according to STEC stx toxin gene positivity rate. Latex agglutination method performed very poor results in suspected strains compared the PCR results (p < 0.05). Conclusions: Meat products sold in markets and butchers carry low but similar risks for infections and epidemics in our region. In the studies that evaluate the presence of the STEC, agglutination methods cannot be trusted alone and, therefore, this test should be combined with at least one of the conventional microbiological or molecular methods.