Search

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 220 clinical isolates of S. aureus were recovered from diverse clinical specimens between August 1, 2019 and June 30, 2020 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 105 (47.72%) of 220 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 100%. 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 [ABSTRACT FROM AUTHOR]

Background: Methicillin resistant Staphylococcus aureus (MRSA) has been emerged as a nosocomial and community acquired pathogen worldwide. There are many challenges for laboratory detection of MRSA. The aim of this study was to compare different phenotypic methods with PCR based method as a gold standard for detection of mecA gene. Methods: A total of 220 clinical isolates of S. aureus which were isolated from various clinical specimens from September 2013 until the June of 2014 in Milad Hospital of Tehran, Iran was subject of our study. Methicillin resistance was determined by oxacillin and cefoxitin disks, oxacillin screen agar and CHROMagar™ MRSA medium. The results of these methods were compared with mecA gene based PCR method as a gold standard method. Results: Among 220 isolates from S. aureus, 105 (47.72%) isolates were positive for mecA gene by PCR method. The results of cefoxitin disk diffusion method with 100% sensitivity and specificity was the same as PCR method .CHROMagar™ MRSA medium had 98.13% sensitivity and 100% specificity. Oxacillin disk diffusion and oxacillin screen agar had 95.42% and 97.22% sensitivity respectively. Conclusion: Result of cefoxitin disk diffusion method with 100% sensitivity and specificity was the same as PCR method for detection mecA gene. Cefoxitin disk diffusion method can be used as an alternative method of PCR for detection of MRSA. [ABSTRACT FROM AUTHOR]