Frequency and Antimicrobial Resistance Patterns of Methicillin-Resistant Staphylococcus aureus in Tehran

Background: Methicillin-Resistant Staphylococcus aureus (MRSA) is the one of most commonly isolated organisms from clinical samples which can cause life- threatening infections. The emergence and spread of antibiotic resistance makes the treatment of these infections more complicated. In this study, we aimed to determine  the  patterns  of  antibiotic  resistance  among  MRSA  isolates  from Tehran, Iran. Methods: From December 2012 to April 2014, 120 clinical samples were collected. MRSA was identified by cefoxitin disc diffusion. Antimicrobial susceptibility testing was performed on MRSA isolates for eight other antibiotics by disc diffusion method according to CLSI (2013) recommendations. Also, the minimum inhibitory concentration (MIC) was determined for vancomycin by MIC test strips. Results: According to disc diffusion, 60 (50%) isolates showed resistance to cefoxitin. Among these isolates, the rate of resistance to nitrofurantoin, vancomycin, teicoplanin, doxycycline, trimethoprim, erythromycin, clindamycin, and ciprofloxacin were 0%, 0%, 0%, 28.3%, 28.3%, 58.3%, 63.3%, and 70%, respectively. All isolates were susceptible to vancomycin according to disc diffusion and MIC. Conclusion: Compared to other reports from Iran, our study indicated a moderate rate  for  MRSA.  However,  the  rates  of  resistance  to  generally  prescribed antibiotics in these isolates were high. In this situation, it is recommended to monitor the antibiotic resistance in these hospitals