COMPARISON OF CEFOXITIN DISC DIFFUSION TEST, OXACILLIN DISC DIFFUSION TEST, OXACILLIN SCREEN AGAR AND PCR FOR MECA GENE FOR DETECTION OF METHICILLIN-RESISTANT STAPHYLOCOCCUS AUREUS (MRSA)

Dr. Hafiza Sultana*, Prof. Humayun Sattar, Dr. Shirin Tarafder, Dr. Jogendra Nath Sarker, Dr. Md Tofael Hossain Bhuiyan Dr. Md. Mostaqimur Rahman and Dr. Md. Abdullah Yusuf

ABSTRACT

Cefoxitin is an efficient inducer of mecA-mediated methicillin resistance (MR) in methicillin-resistant S. aureus (MRSA). It is recommended by Clinical and Laboratory Standards Institute (CLSI) guideline (2010)/ different studies to use cefoxitin in disc diffusion method for the detection of MRSA. Therefore, the aim of this study to evaluate the efficiency of cefoxitin disc diffusion in comparison to oxacillin disc diffusion and oxacillin screening agarin the detection of mecA-mediated MR in S. aureus where PCR for mecA gene detection was ‘gold standard’. This cross-sectional study was carried out in the Department of Microbiology and Immunology at Bangabandhu Sheikh Mujib Medical University, Dhaka from January, 2010 to December, 2010 for a period of one (01) year. S. aureus isolates were collected from different clinical samples including wound swab, pus, blood, urine, tracheal aspirate, throat swab, aural swab etc. Staphylococcus aureus (S.aureus) were isolated and confirmed by staing, biochemical tests. Routine antimicrobial susceptibility testing was performed cefoxitin discs diffusion test. PCR was performed for detection of the mecA gene for MRSA. In this study 120 isolated strains of S. aureus was included from different clinical specimens and antimicrobial susceptibility was performed according to CLSI guidelines. The sensitivity and specificity of oxacillin disc diffusion was 84.2% & 66.2%, oxacillin screen agar was 100.0% & 33.3% respectively where in cefoxitin disc diffusion both was 100.0% and matches with the result of PCR. So, the cefoxitin disc diffusion can be the alternative to technically demanding PCR in the detection of MRSA.

Keywords: methicillin-resistant S. aureu; mecA gene; cefoxitin disc diffusion test; oxacillin disc diffusion test; oxacillin screen agar; PCR.