Study on the antibiotic resistance of E.coli isolated from raw milk and unpasteurized cheese and survey on resistance transmission to E.coli O2:K12

This study was conducted to determine the antibiotic resistance of E.coli isolated from raw milk and un pasteurized cheese. A total of 50 isolates were examined by Disk diffusion method and 47 (94 %) out of 50 isolates showed resistance against one or more of using antibiotics. The resistance against antibiotics were 27.65% for Tetracycline, 4.25 %for Streptomycin, 4.25% for Amikacin, 23.4% for Ampicillin, 8.51 %for Nitrofurantoin, 6.38% for Gentamycin, 2.12 % for Trimetoprim, 4.25 % for Ciprofloxacin and 80.85 for Clindamaycin. All of the isolates were susceptible to Neomycin and Norfloxacin. Also, the result showed that 44 %, 28%, 12% and 10% of the isolates were resistant to one, two, three and four antibiotics, respectively. Regarding to the results, 6.35% of the isolates transferred their resistance factor to E.coli O2K12 strain. The results of this study revealed that contamination of foods with the resistant strains may lead to transferring the resistant factors to consumer gut micro flora, thus it may considered as a risk for public health.