Detection of Methicillin Resistant Staphylococcus aureus (MRSA) by CHROMagar Versus Cefoxitin Disk Diffusion Method

Background and Aim: MRSA, or methicillin-resistant Staphylococcus aureus, has arisen as a nosocomial and community-acquired infection throughout the world. MRSA identification in the laboratory is difficult for a variety of reasons. The aim of this study was to investigate several phenotypic methods for the detection of MRSA compared with the PCR-based method as the gold standard. Materials and Methods: A total of ۲۲۰ clinical isolates of S. aureus were recovered from diverse clinical specimens between August ۱, ۲۰۱۹ and June ۳۰, ۲۰۲۰ at Milad Hospital in Tehran, Iran. Cefoxitin discs, CHROMagar™ MRSA medium, and identification of the mecA gene by Polymerase Chain Reaction (PCR) as the gold standard method were used to assess methicillin resistance. Results and Conclusion: PCR testing revealed that ۱۰۵ (۴۷.۷۲%) of ۲۲۰ S. aureus isolates were positive for the mecA gene. The results of the Cefoxitin disc diffusion method showed that it has similar sensitivity and specificity to PCR method. The sensitivity and specificity of CHROMagar™ MRSA medium were both ۱۰۰%. The Cefoxitin disc diffusion method had the same sensitivity and specificity as the PCR method for detecting the mecA gene. For MRSA detection, the Cefoxitin disc diffusion method can be employed as an alternative to PCR.

Keywords:

Methicillin Resistant , mecA gene , Staphylococcus aureus , CHROMagar , MRSA , مقاوم به متی سیلین , ژن mecA , استافیلوکوکوس اورئوس , CHROMagar , MRSA