Reza Robati and Sakineh Gholami
The purpose of this study is isolation and identification of Escherchia coli 0157:H7 virulence genes from juice purchase and vegetables in Tehran. This cross-sectional study was performed on 200 samples of juice purchase and vegetables collected from Tehran. Isolates were enriched in ECB with novobiocin medium in temperature 37�?¢�?�??�?¦ C. After, in order to examine the fermentation of sorbitol and lactose the CT-SMAC and VRBA media and the activities of β-glucoronidase of separated bacteria were examined using the choromoagar medium. Then, the existence of E.coli 0157:H7 was confirmed with the specific antiserum. Finally, virulence genes stx1, stx2, eae and hly were tested by multiplex PCR and rfb O157 and fliC H7 were tested by single PCR. Out of all examined samples 156(78%) sorbitol negative bacteria were separated that after evaluation with specific antiserum 46 (23%) E.coli 0157:H7 was detected. The molecular markers, stx1 genes in 7 samples and eae, stx1 in 1 sample were detected. Intensive studies of the sources, incidence, fate and transport of E.coli 0157:H7 near produce production are required to determine the mechanisms of pre-harvest contamination and potential risks for humans.
