Performance of MicroScan WalkAway and Vitek 2 for Detection of Oxacillin Resistance in a Set of Methicillin-Resistant Staphylococcus aureus Isolates with Diverse Genetic Backgrounds

Of 104 genotypically diverse methicillin-resistant Staphylococcus aureus (MRSA) isolates tested with the MicroScan WalkAway (Pos MIC 24 panel) and Vitek 2 (AST-P549 card) systems, 7 and 6 isolates, respectively, showed an oxacillin MIC of <= 2mg/liter. Most of these MRSA isolates were community acquired. However, if the cefoxitin screen of AST-P549 was also considered, MRSA detection failed for only one isolate.