Abstract: Objective To evaluate the in vitro activities of ravuconazole and fluconazole against clinical and environmental isolates. Methods The in vitro activities of ravuconazole and fluconazole aganist 77 isolates of Cryptococcus neoformans were tested according to M27-A microdilution method recommended by National Committee for Clinical Laboratory Standards (NCCLS). Results The MICs of fluconazole ranged from 2.0 to 128 μg/mL, with the geometric mean MIC₅₀ and MIC₉₀ of 4 μg/mL, 8 μg/mL. The ravuconazole MICs ranged from 0.008 to 0.5 μg/mL, with the geometric mean MIC₅₀, MIC₉₀ of 0.125 μg/mL, 0.25 μg/mL. 81.8% (63/77) isolates were sensitive to fluconazole, 16.9% (13/77) isolates were dose-dependent sensitive to fluconazole, 1.3% (1/77) isolates were resistant to fluconazole. The clinical and environmental isolates had the similar MIC to fluconazole and ravuconazole (P>0.05). Conclusion It is encouraging that ravuconazole is effective against clinical and environmental isolates of C. neoformans, whether the isolates were sensitive to fluconazole or not.

Key words: Cryptococcus neoformans, Fluconazole, Ravuconazole, Microbial sensitivity tests