ORGANISM-DEPENDENT FUNGICIDAL ACTIVITIES OF AZOLES

We investigated the antifungal activities of itraconazole and voricona zole on Aspergillus species by time kill studies, and the results were compared with those obtained for Candida species. Exposure of Aspergi llus fumigatus conidia to varying concentrations (1.25 to 10 mu g/ml) of itraconazole and voriconazole resulted in cellular death; the cytoc idal effect was time and concentration dependent. In contrast, no kill ing of Candida albicans occurred in the presence of itraconazole and v oriconazole at concentrations as high as 10 mu g/ml, although candidal growth was inhibited compared to the drug-free control. Amphotericin B (1.25 to 10 mu g/ml), on the other hand, killed both A. fumigatus an d C. albicans. Similar results were obtained for non-A. fumigatus aspe rgilli and non-C. albicans Candida species. These observations indicat e that both itraconazole and voriconazole are cytocidal agents for Asp ergillus species but not for Candida species, suggesting that azoles p ossess organism-dependent fungicidal activities.