Abstract

This study was based on the comparison of revised guidelines of Clinical and Laboratory Standard Institute (CLSI), British Society for Antimicrobial Chemotherapy (BSAC) and Brilliance^TM MRSA agar (Oxoid) for the phenotypic identification of methicillin resistantStaphylococcus aureus (MRSA). A total of 133 clinical isolates of S. aureus were tested using new CLSI, BSAC guidelines and Brilliance^TM MRSA Agar. All the strains were tested according to prescribed guidelines of CLSI (M100-S20, 2010) and BSAC (10.2, 2011). The 30 µg and 10 µg cefoxitin (FOX) performed best for the detection of MRSA and gave 100% sensitivity and specificity. While 1 µg oxacillin (OX) showed less effective results showing sensitivity and specificity of 96.8% and 100% respectively. The cefoxitin disc diffusion method appears to be a good option for the identification of MRSA. Brilliance^TM MRSA agar when used for the detection of MRSA, showed sensitivity and specificity of 98.4% and 100% respectively. In conclusion the efficiency of FOX is very high and FOX disc diffusion method is the most efficient method for the identification of MRSA phenotypicallyand could be a second choice for the detection of MRSA.

Key words: Staphylococcus aureus, CLSI, BSAC, Chromogenic media, MRSA.