en Microbiology Microbiology پژوهشي Research <div dir="ltr"> <p style="text-align: justify;"><strong>Introduction: </strong>In this study, using the phenotypic and genotypic methods, oxacillin susceptibility in <em>Staphylococcus aureus</em> (<em>S. aureus</em>) strains isolated from patients at two government hospitals in Ilam, Iran was tested.</p> <p style="text-align: justify;"><strong>Materials and methods:</strong> Out of 200 <em>S. aureus</em> isolates from different human clinical specimens consisting of blood (31%), wound (20%), urine (21%), catheters (7%), sputum (12%), others (9%) were collected. The methicillin resistant <em>S. aureus</em> isolates were investigated using disk diffusion methods and oxacillin (1&mu;g) and cefoxitin (30&mu;g), on Mueller-Hinton agar were used, and <em>MecA</em> and <em>vanA</em> genes were detected by PCR. In addition, the isolates were tested for their antibiogram profiles.</p> <p style="text-align: justify;"><strong>Results: </strong>Among 200 <em>S. aureus</em> strains included in this study, 35.96% were MRSA. The percentage of resistance by disk diffusion method was as below: penicillin 85.96%, vancomycin 0%, ampicillin 87.71%, gentamicin 48.25% erythromycin 54.25%, clindamycin 32.45%, amikacin 21.05%, ciprofloxacin 42.10%, tetracycline 51.75% and co-trimoxazole 42.10%. Phenotyping method by disk diffusion method using oxacillin and cefoxitin for detecting of MRSA showed sensitivity and specificity of about 33.33% and 35.96%, respectively. Presence of <em>MecA</em> and <em>vanA</em> genes in MRSA isolates by PCR were 35.96% and 0%, respectively. The oxacillin and cefoxitin disk diffusion methods showed 92.68% and 100% sensitivity, respectively, and 98.8% specificity.</p> <p style="text-align: justify;"><strong>Conclusion:</strong> Our finding showed that, the cefoxitin disk diffusion method is better in compared to the oxacillin disk diffusion similar to results from detecting of <em>MecA</em> gene in PCR as a golden test.</p> </div> Staphylococcus aureus, MecA, Methicillin, Vancomycin 1 6 http://jbrms.medilam.ac.ir/browse.php?a_code=A-10-136-1&slc_lang=en&sid=1 Arman Rostamzad arostamzad381@yahoo.com 10031947532846001894 10031947532846001894 Yes Department of Biology Faculty of Sciences, Ilam University, Ilam, Iran Nabi Rostamneia nabi.biology@gmail.com 10031947532846001895 10031947532846001895 No Department of Biology Faculty of Sciences, Ilam University, Ilam, Iran Fazel Pourahmad f.pourahmad@ilam.ac.ir 10031947532846001896 10031947532846001896 No School of Veterinary Medicine, Ilam University, Ilam, Iran Morteza Shamsi arostamzad381@yahoo.com 10031947532846001897 10031947532846001897 No Department of Parasitology, Faculty of Medicine, Ilam University of Medical Sciences, Ilam, Iran