Abstract

Background: Pyogenic bacteria and especially Staphylococcus aurous (S. aurous) are the most common cause of chronic osteomyelitis. Not only treatment protocol of chronic osteomyelitis occasionally is amiss but also this malady responds to treatment difficultly. Objectives: This study investigates antibiotic resistance pattern of S. aurous isolated from Iranian patients who suffer from chronic osteomyelitis by two methods: disk diffusion (Kirby bauyer) and E-test (Epsilometer test) to find Vancomycin susceptibility and MIC (Minimum inhibitory concentration). Patients and Methods: One hundred and thirty one patients who suffer from chronic osteomyelitis which have been referred to both governmental and private hospitals at 2010 were tried out for culturing of osteomyelitis site (sites). Antibiotic susceptibility and MIC of isolated bacteria were investigated by Kirby bauyer and E-test respectively. Results: Samples were collected from bone (73.4), surrounding tissue (14.6) and wound discharge (12). S. aureus was isolated from 49.6 of the samples. According to disc diffusion, methicillin resistance S. aureus (MRSA) was 75 and Vancomycin resistance S. aurous (VRSA) was 0 and based on MIC, MRSA was 68.5 and VRSA was 0. According to MIC experiments, maximum sensitivity was against to Vancomycin (90.2) and ciprofloxacin (54.4) respectively but based on disc diffusion, maximum sensitivity was against to Vancomycin (97.7) and ciprofloxacin( 43.2), respectively (P = 0.001). E-test (9.8) in comparison with Disc diffusion (2.3) showed higher percent of intermediate susceptibility to Vancomycin (P = 0.017). Conclusions: Comparison of antibiograms and MICs showed that Kirby bauyer technique especially for detection of VISA strains is not reliable comparison with E-test. Already VRSA strains have not detected in Iranian chronic osteomyelitis, Thus Vancomycin is the first choice for chronic osteomyelitis empirical therapy in Iran yet.