Razi Journal of Medical Sciences

Background: Staphylococcus aureus is a facultative anaerobic Gram-positive coccal bacterium which is frequently found as part of the normal flora on the skin and nasal passages. S. aureus can cause a range of illnesses from minor skin infections to life-threatening diseases. The organism is able to developresistance to a wide range of antibiotics. Resistance to antibiotic is one of the major public health problems and, nowadays, widespread use of antibiotics is playing a significant role in the emergence of theresistant bacteria. The aim of this study was to detect antibiotic resistance of different strains of S. aureus to current antibiotics.

Methods: This cross-sectional descriptive study was performedon eight different strains of S. aureus. Initially, appropriate samplesweretakenand then, the morphological, chemical or enzymatic tests were doneto confirm diagnosis. Finnally, using disc diffusion agar, the effects of different antibiotic discs were evaluated.

Results: All strains were sensitive to six antibiotics includingChlorotetracycline, Gentamycin, Oxytetracycline, Trimethoprim -Sulfametoxasol,Rifampicin and Tobramycin,while all strains were resistant just to three antibiotics including Vancomycin, Oxacillin and Ceftazidime. Each strain showed different sensitivity and resistance rate to other antibiotics.

Conclusions: With due regard to the differences in antibioticssensitivity and resistance rate in different strains, evaluation of antibiotic resistance is necessary for treatment of microbial infections.