Sensititre YeastOne (YO) panels were assessed for in vitro susceptibility testing of echinocandins against 39 isolates of Aspergillus fumigatus, A. flavus, and A. terreus, including two echinocandin-resistant A. fumigatus strains, using different inocula (103, 104, and 105 CFU/ml), incubation times (16 to 48 h), and endpoints (first blue or purple well) and compared to CLSI M38-A2. The best agreement was found with an inoculum of 104 CFU/ml, incubation times of 20 h for A. flavus and of 30 h for A. fumigatus and A. terreus, and reading the first purple well. The reproducibility within ±1 2-fold dilutions was 100% for all three echinocandins. YO color endpoints were 2 to 3 2-fold dilutions lower than CLSI minimum effective concentrations (MECs) of caspofungin and 1 to 2 2-fold dilutions higher than CLSI MECs of micafungin. For anidulafungin, off-scale YO color endpoints were observed. Nevertheless, A. fumigatus echinocandin-resistant isolates were detected after 24 h of incubation.

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Journal of Clinical Microbiology
Department of Medical Microbiology and Infectious Diseases

Siopi, M., Pournaras, S., & Meletiadis, J. (2017). Comparative evaluation of sensititre YeastOne and CLSI M38-A2 reference method for antifungal susceptibility testing of Aspergillus spp. against echinocandins. Journal of Clinical Microbiology, 55(6), 1714–1719. doi:10.1128/JCM.00044-17