Echinocandin and triazole antifungal susceptibility profiles for Candida spp., Cryptococcus neoformans, and Aspergillus fumigatus: application of new CLSI clinical breakpoints and epidemiologic cutoff values to characterize resistance in the SENTRY Antimicrobial Surveillance Program (2009)

Abstract

The SENTRY Antimicrobial Surveillance Program monitors global susceptibility and resistance rates for newer and established antifungal agents. The echinocandins displayed excellent potency against both Candida spp. and Aspergillus fumigatus in 2009 samples. Using the new Clinical and Laboratory Standards Institute breakpoint values for the echinocandins when testing Candida spp., we demonstrate low but measurable rates of resistance to all 3 echinocandins (anidulafungin, caspofungin, and micafungin) when tested against Candida glabrata. Three of the 8 isolates demonstrating in vitro echinocandin resistance harbored fks resistance mutations, including 1 C. glabrata. The triazoles, with the exception of itraconazole, also exhibited excellent potency and low levels of resistance when tested against clinical isolates of Candida spp., Cryptococcus neoformans, and A. fumigatus. Overall, echinocandin and triazole resistance rates were minimal; however, the distinct increase in echinocandin resistance observed among C. glabrata strains warrants further surveillance associated with molecular support.