Study of the contamination of traditional cheeses produced in Maragheh city to Escherichia coli O157:H7

This study was conducted in villages of Maragheh city to determine the contamination of Escherichia coli O157: H7 in traditional cheeses. A total of 100 cheese samples were cultured in Tryptic soy broth containing cefixime and then they were transferred to Mac conkey sorbitol agar containing cefixime and potassium tellurite. Suspicious colonies were stained (Gram staining) and identified by IMVC and other tests. Isolated Escherichia coli were tested for detection of O and H serotypes by direct agglutination method. Cheese samples were also tested for pH and NaCl content. Antibiogram test was done on Escherichia coli isolates by Kirby-bauer’s method. No Escherichia coli O157: H7was detected in the studied samples. In this study، other serotypes of Escherichia coli were isolated containing 32 non O157 serotypes. These serotypes including، Enteropathogenic (O55، O127، O86، O114، O44، O126، O125)، Enterotoxigenic (O20، O128) and Verotoxigenic (O26، O111). All of the isolated strains were resistant to Ampicillin and Polymyxin B. The effect of prevalence ratio of Escherichia coli serotypes from pH and NaCl content was not significant statistically (p>0. 05). From the results of this study it seems that traditional cheese could be a potent carrier to transmit the various serotype of Escherichia coli and cause disease in human.