TABLE 1.

Comparison of the oxacillin MIC determination and the OR test of the VITEK 2 system with the results of the mecA PCR

Parameter and strainNo. of strains
Concordant results between mecA PCR and both     MIC and OR test179
    mecA-positive strains119
    mecA-negative strains60
Indeterminate results (discrepancies between     MIC and OR test) for:16
    mecA-negative strains
        S. saprophyticus group9
        S. lugdunensis4
        S. epidermidis1
    mecA-positive strains
        S. epidermidis1
        S. hominis1
False-positive results (mecA-negative strain, but both MIC and OR test indicated resistance)1
False-negative results (mecA-positive strain, but both MIC and OR test indicated susceptibility1
Insufficient growth3