In vitro susceptibility of clinical isolates of Aspergillus spp. to anidulafungin, caspofungin, and micafungin: a head-to-head comparison using the CLSI M38-A2 broth microdilution method.

We determined the in vitro activities of anidulafungin, caspofungin, and micafungin against 526 isolates of Aspergillus spp. (64 A. flavus, 391 A. fumigatus, 46 A. niger, and 25 A. terreus isolates) collected from over 60 centers worldwide from 2001 through 2007. Susceptibility testing was performed according to the CLSI M38-A2 method. All three echinocandins--anidulafungin (50% minimum effective concentration [MEC50], 0.007 microg/ml; MEC90, 0.015 microg/ml), caspofungin (MEC50, 0.015 microg/ml; MEC90, 0.03 microg/ml), and micafungin (MEC50, 0.007 microg/ml; MEC90, 0.015 microg/ml)-were very active against Aspergillus spp. More than 99% of all isolates were inhibited by < or = 0.06 microg/ml of all three agents.