Isolation, genotyping and antimicrobial susceptibility of pathogenic Escherichia coli serotypes in ready to eat foods

In this study, pathogenic E. coli serotypes ( E. coli O157:H7, 026, 0111) and their molecular proximity and antimicrobial susceptibility were investigated in RTE foods. A total of 240 samples were analyzed consisting of 105 stuffed mussel, 56 meatless cig kofte, 54 Russian salad, 25 cheese halva. The conventional cultural and serotyping methods for determination of the organisms in samples were performed and further confirmed by polymerase-chain reaction (PCR). All of the confirmed E. coli O157 isolates were genotyped by the enterobacterial repetitive intergenic consensus (ERIC)-PCR. Antibacterial susceptibility testing of the isolates was performed by disc diffusion method. E. coli was detected in 7 (2.9 %) of 240 samples, including 3 (5.5%) Russian salad, 3 (2.8%) stuffed mussel, 1 (4 %) cheese halva. Two isolates from Russian salad were identified as E. coli O157, one isolate from stuffed mussel and one isolate from cheese halva were also identified as E. coli O157:H7. In addition, it was found that stuffed mussel isolate carried stx 1 ve hly A genes whereas one Russian salad isolate carried the stx 1 gene. E. coli isolates were found to be resistant to amoxycillin+clavulonic acid (AMC), gentamicin (CN) and ciprofloxacin (CP), at the rate of 29%, 14% and 29 %, respectively. Only one (14 %) isolate from stuffed mussel was classified as multidrug resistant (AMC, CN and CP). Furthermore, the isolates, related to O157 and O157:H7, presented different ribotypes in this study. The results provides useful information for the development of public health policy for the presence of pathogenic antimicrobial resistant E. coli serotypes in RTE foods.