fa ردیابی ژن sul2 در اشریشیاکلی جداسازی شده از بیماران مبتلا به عفونت‌های ادراری مراجعه کننده به مراکز کلینیکی شهر خوی کارآزمایی بالینی Clinical Trials Background and Objective Widespread use of co-trimoxazole in urinary tract infection treatments and its incorrect use has led to the emergence of co-trimoxazole resistant E. coli strains. The aim of this study was to evaluate sul2 gene among E.coli isolates of patients admitted to the clinical centers of Khoy city. Materials and Methods: Three hundred urine samples were collected from clinical centers of Khoy city. Among them, 100 E.coli isolates were confirmed by standard biochemical tests. Furthermore, the antibiotic susceptibility tests to 10 antibiotics were performed by the-disk-agar diffusion (DAD) method. Also, MIC and MBC were evaluated for co-trimoxazole by microdilution broth method. Finally, PCR was done in order to find sul2 gene in resistant isolates. Results: Of 100 isolates, 71(71%) were resistant to co-trimoxazole out of which 57(80%) had sul2 gene. This gene was recognized in sulfonamides-resistant isolates which did not create any zone of inhibition. Also, the isolates with sul2 gene were found to be simultaneously resistant to ampicillin, nalidixic acid and ciprofloxacin. In co-trimoxazole-resistant isolates, MIC and MBC for Co-trimoxazole were calculated 16 and 32μg/ml. Conclusion: This study was the first of its kind in Iran with the main objective of manifesting the presence of sul2 gene in E.coli. The results of the present study indicate that antibiotic-resistance percentage in Khoy city reaches to 71%. In such a situation, it is inevitable to see resistance to all common antibiotics currently prescribed to patients at clinical centers which will, in turn, result in treatment failures. Keywords: Escherichia coli, Sulfonamides, sul2 gene, Antibiotic resistance, disk-diffusion method, MIC 76 83 http://journal.zums.ac.ir/browse.php?a_code=A-10-4-739&slc_lang=fa&sid=1 Jamileh Norouzi جمیله نوروزی 5200319475328460059480 5200319475328460059480 No Dept. of Microbology, Islamic Azad University, North Tehran Branch, Tehran, Iran Abbas Akhavan sepahy عباس اخوان سپهی 5200319475328460059481 5200319475328460059481 No Dept. of Microbology, Islamic Azad University, North Tehran Branch, Tehran, Iran Negar Bazzazzadeh نگار بزاززاده bazzazzadeh_n92@yahoo.com 5200319475328460059482 5200319475328460059482 Yes Islamic Azad University, North Tehran Branch, Tehran, Iran