Wild-Type MIC Distributions and Epidemiological Cutoff Values for the Echinocandins and Candida spp

Abstract

We tested a global collection of Candida sp. strains against anidulafungin, caspofungin, and micafungin, using CLSI M27-A3 broth microdilution (BMD) methods, in order to define wild-type (WT) populations and epidemiological cutoff values (ECVs). From 2003 to 2007, 8,271 isolates of Candida spp. (4,283 C. albicans , 1,236 C. glabrata , 1,238 C. parapsilosis , 996 C. tropicalis , 270 C. krusei , 99 C. lusitaniae , 88 C. guilliermondii , and 61 C. kefyr isolates) were obtained from over 100 centers worldwide. The modal MICs (in μg/ml) for anidulafungin, caspofungin, and micafungin, respectively, for each species were as follows: C. albicans , 0.03, 0.03, 0.015; C. glabrata , 0.06, 0.03, 0.015; C. tropicalis , 0.03, 0.03, 0.015; C. kefyr , 0.06, 0.015, 0.06; C. krusei , 0.03, 0.06, 0.06; C. lusitaniae , 0.05, 0.25, 0.12; C. parapsilosis , 2, 0.25, 1; and C. guilliermondii , 2, 0.5. 05. The ECVs, expressed in μg/ml (percentage of isolates that had MICs that were less than or equal to the ECV is shown in parentheses) for anidulafungin, caspofungin, and micafungin, respectively, were as follows: 0.12 (99.7%), 0.12 (99.8%), and 0.03 (97.7%) for C. albicans ; 0.25 (99.4%), 0.12 (98.5%), and 0.03 (98.2%) for C. glabrata ; 0.12 (98.9%), 0.12 (99.4%), and 0.12 (99.1%) for C. tropicalis ; 0.25(100%), 0.03 (100%), and 0.12 (100%) for C. kefyr ; 0.12 (99.3%), 0.25 (96.3%), and 0.12 (97.8%) for C. krusei ; 2 (100%), 0.5 (98.0%), and 0.5 (99.0%) for C. lusitaniae ; 4 (100%), 1 (98.6%), and 4 (100%) for C. parapsilosis ; 16 (100%), 4 (95.5%), and 4 (98.9%) for C. guilliermondii . These WT MIC distributions and ECVs will be useful in surveillance for emerging reduced echinocandin susceptibility among Candida spp. and for determining the importance of various FKS1 or other mutations.