In vitro susceptibility of chromoblastomycosis and phaeohyphomycosis agents to antifungal drugs

The in vitro susceptibility of chromoblastomycosis and phaeohyphomycosis agents to antifungal drugs was appraised using the reference macrodilution method proposed by the National Committee for Clinical Laboratory Standards (NCCLS) for yeasts modified for filamentous fungi. The antifungal drugs amphotericin B, 5-fluorocytosine, itraconazole and fluconazole were tested against one environmental and 18 clinical isolates. This work amended the macrodilution methods proposed by NCCLS and suggests that a conidial suspension free of hyphae leads to a more reliable assay and provides for better reproducibility. The macrodilution method was performed with 104 conidia ml−1. The MIC values ranged from 1·0 to 16·0 μg ml−1 for amphotericin B and 3·12 to 25·0 μg ml−1 for 5-fluorocytosine. A MIC range of 0·06 to 1·95 μg ml−1 was determined for itraconazole while 2·0 to 64·0 μg ml−1 was detected for fluconazole.