In vitro activities of anidulafungin against more than 2,500 clinical isolates of Candida spp., including 315 isolates resistant to fluconazole.

Anidulafungin is an echinocandin antifungal agent with potent activity against Candida spp. We assessed the in vitro activity of anidulafungin against 2,235 clinical isolates of Candida spp. using the CLSI broth microdilution method. Anidulafungin was very active against Candida spp. (the MIC at which 90% of strains are inhibited [MIC(90)] was 2 microg/ml when MIC endpoint criteria of partial inhibition [MIC-2] were used). Candida albicans, C. glabrata, C. tropicalis, C. krusei, and C. kefyr were the most susceptible species of Candida (MIC(90), 0.06 to 0.12 microg/ml), and C. parapsilosis, C. lusitaniae, and C. guilliermondii were the least susceptible (MIC(90), 0.5 to 2 microg/ml). In addition, 315 fluconazole-resistant isolates were tested, and 99% were inhibited by < or =1 microg/ml of anidulafungin. These results provide further evidence for the spectrum and potency of anidulafungin activity against a large and geographically diverse collection of clinically important isolates of Candida spp.