The probe-based Velogene Rapid MRSA Identification Assay (ID Biomedical Corp., 
Vancouver, British Columbia, Canada) and the latex agglutination MRSA-Screen 
(Denka Seiken Co., Tokyo, Japan) were evaluated for their ability to identify 
methicillin-resistant Staphylococcus aureus (MRSA) and to distinguish strains of 
MRSA from borderline oxacillin-resistant S. aureus (BORSA; mecA-negative, 
oxacillin MICs of 2 to 8 microgram/ml). The Velogene is a 90-min assay using a 
chimeric probe to detect the mecA gene. MRSA-Screen is a 15-min latex 
agglutination test with penicillin-binding protein 2a antibody-sensitized latex 
particles. We compared these assays with the BBL Crystal MRSA ID System (Becton 
Dickinson, Cockeysville, Md.) and with PCR for mecA gene detection. A total of 
397 clinical isolates of S. aureus were tested, consisting of 164 
methicillin-susceptible strains, 197 MRSA strains, and 37 BORSA strains. All 
assays performed well for the identification of MRSA with sensitivities and 
specificities for Velogene, MRSA-Screen, and BBL Crystal MRSA ID of 98.5 and 
100%, 98.5 and 100%, and 98.5 and 98%, respectively. Three MRSA strains were not 
correctly identified by each of the Velogene and MRSA-Screen assays, but repeat 
testing with a larger inoculum resolved the discrepancies. The BBL Crystal MRSA 
ID test misclassified four BORSA strains as MRSA. Both the Velogene and the 
MRSA-Screen assays are easy to perform, can accurately differentiate BORSA 
isolates from MRSA isolates, and provide a rapid alternative for the detection 
of methicillin resistance in S. aureus in clinical laboratories, especially when 
mecA PCR gene detection is unavailable.