In Vitro Activity of Voriconazole Against Candida Species

The in vitro activity of voriconazole was compared with that of itraconazole and fluconazole against 181 isolates of Candida albicans, 124 isolates of Candida glabrata, and 20 isolates of Candida krusei obtained from the early 1980s through the mid-1990s. Voriconazole had greater intrinsic activity than fluconazole or itraconazole against all three Candida species. For C. glabrata, C. krusei, and C. albicans, the MIC50 values for voriconazole were 1 microgram/mL, 0.5 microgram/mL, and 0.01 microgram/mL, respectively compared with fluconazole MIC50 values of 8 micrograms/mL, 64 micrograms/mL, and 0.25 microgram/mL, respectively. If isolates from AIDS patients were excluded, MIC values for isolates from the 1990s were no higher than those noted for isolates from the 1980s. Voriconazole, a new triazole antifungal agent, appears to have enhanced activity against these three species of Candida; the clinical relevance of these findings should be studied in treatment trials.