In Vitro Activity of Isavuconazole and Comparator Antifungal Agents Tested Against a Global Collection of Opportunistic Yeasts and Moulds.
J Clin Microbiol. 2013 Jun 5;
Authors: Pfaller MA, Messer SA, Rhomberg PR, Jones RN, Castanheira M
BACKGROUND: Isavuconazole is a new broad-spectrum triazole with a favorable pharmacokinetic and safety profile.METHODS: We report the MIC distributions for isavuconazole and 111 isolates of Candida (C. albicans [42 isolates], C. glabrata (25), C. parapsilosis (22), C. tropicalis (14), and C. krusei (8)) as determined by both CLSI and EUCAST broth microdilution (BMD) methods; also the comparative activity of isavuconazole, itraconazole, fluconazole, posaconazole, voriconazole and the three echinocandins was assessed against a recent (2011) global collection of 1,358 isolates of Candida spp., 101 of Aspergillus spp., 54 of non-Candida yeasts, and 21 of non-Aspergillus moulds as determined by CLSI BMD methods.RESULTS: The overall essential agreement (EA; ± two log2 dilutions) between the CLSI and EUCAST methods was 99.1% (EA ± 1 log 2 dilution, 90.1% [range 80.0-100.0%]). The activity of isavuconazole against the larger collection of Candida spp. and Aspergillus spp. was comparable to that of posaconazole and voriconazole: MIC90 values for these 3 triazoles against Candida spp. was 0.5, 1 and 0.25 μg/ml, respectively and against Aspergillus spp. was 2, 1 and 1 μg/ml, respectively. Isavuconazole showed good activity against Cryptococcus neoformans (MIC90, 0.12 μg/ml) and other non-Candida yeasts (MIC90, 1 μg/ml), but was less potent against non-Aspergillus moulds (MIC90, >8 μg/ml). MIC values for isavuconazole and three mucormycetes isolates were 4, 1 and 2 μg/ml, respectively, whereas all three were inhibited by 1 μg/ml of posaconazole.CONCLUSIONS: Isavuconazole demonstrates broad-spectrum activity against this global collection of opportunistic fungi and both CLSI and EUCAST methods may be used to test this agent against Candida with highly comparable results.
PMID: 23740727 [PubMed - as supplied by publisher]