Multicenter comparison of the Vitek 2 antifungal susceptibility test with the CLSI broth microdilution reference method for testing caspofungin, micafungin, and posaconazole against Candida spp.

The performance of the automated Vitek 2 (bioMérieux, Inc., Marcy l'Etoile, France) antifungal susceptibility system was compared to that of broth microdilution (BMD) for the determination of MICs of various antifungal drugs. A total of 112 challenge strains and 755 clinical isolates of Candida spp. were tested against caspofungin and micafungin. An additional 452 clinical isolates of Candida albicans were tested against posaconazole. Reference BMD MIC endpoints were established after 24 h of incubation for caspofungin and micafungin and after 48 h of incubation for posaconazole. Essential agreements (EAs) between the Vitek 2 and BMD methods for caspofungin and micafungin were 99.5% and 98.6%, respectively. EA between the Vitek 2 and BMD methods was 95.6% for posaconazole. The overall categorical agreements (CAs) between the Vitek 2 system and BMD were 99.8% for caspofungin, 98.2% for micafungin, and 98.1% for posaconazole. The Vitek 2 system reliably determined caspofungin and micafungin MICs among Candida spp. and posaconazole MICs among C. albicans isolates and demonstrated excellent quantitative and qualitative agreement with the reference BMD method.