In Vitro Activities of Vancomycin, Fosfomycin, Fusidic Acid and Linezolid Against Methicillin-Resistant Staphylococcus aureus, Year 2011-2012

Objective: To determine in vitro activities of vancomycin, fosfomycin, fusidic acid and linezolid against methicillin-resistant Staphylococcus aureus (MRSA) isolated in Songklanagarind Hospital, collected during the period July 2011 to December 2012. Material and Method: The minimum inhibitory concentrations (MICs) of these antibiotics were determined by the Epsilon-test method, and heterogeneous vancomycin-intermediate Staphylococcus aureus (hVISA) screening was done by one point population analysis (OPA). Results: Of the 96 MRSA isolates tested, the results showed 100 percent susceptibility to vancomycin, linezolid and fusidic acid, but only 46 percent susceptibility to fosfomycin. No hVISA was found among MRSA screened by one point population analysis. Conclusion: MRSA isolates in Songklanagarind Hospital are still susceptible to standand anti-MRSA except for fosfomycin, and a surveillance for hVISA screening should be continued.