Frequency of fks Mutations among Candida glabrata Isolates from a 10-Year Global Collection of Bloodstream Infection Isolates

Among 119 echinocandin non-wild-type (non-WT) Candida glabrata strains from two global surveys, mutations in fks hot spots (HSs) were detected in 28 (from 7 countries and 8 U.S. states): 24 strains (85.7%) had non-WT MICs for micafungin, 22 (78.6%) for anidulafungin, and 25 (89.3%) for caspofungin. The most common FKS substitutions among non-WT strains were at positions F659 (n = 7) and S663 (n = 7). Three isolates displaying WT MIC results had F625Y, L630I, and D632Y substitutions or non-HS mutations. Mutations that have been reported to decrease the echinocandin binding to the 1,3-beta-D-glucan synthase were categorized as resistant by applying the new CLSI breakpoint criteria for all three echinocandins.