Evaluation of commercial vancomycin agar screen plates for detection of vancomycin-resistant enterococci

Abstract

Brain heart infusion-6-μg/ml vancomycin agar plates obtained from five commercial sources (B-I) Microbiology Systems, Carr-Scarborough Microbiologicals, MicroBio Products, PML Microbiologicals, and REMEL) were evaluated with 714 enterococci for detection of vancomycin resistance. All 465 (100%) vancomycin-resistant enterococci (MIC ≤ 32 μg/ml) were detected by each manufacturer's agar screen plate, and each manufacturer's agar screen plate detected at least 99% of the 177 vancomycin-susceptible enterococci (MIC ≤ 4 μg/ml). Detection of the 72 vancomycin-intermediate enterococci (MIC = 6 to 16 μg/ml) ranged from 94% for B-D Microbiology Systems to 99% for PML Microbiologicals.