[In vitro activity of amphotericin B, fluconazole and itraconazole against Candida glabrata strains isolated from clinical samples]

Abstract

In recent years, the incidence of Candida albicans infections tends to decrease, at least in some centers other Candida species have emerged as opportunistic pathogens. Among non-albicans Candida species, C. glabrata is one of the most frequently isolated species. In this study, the in vitro activities of amphotericin B, itraconazole and fluconazole were tested against 134 clinical C. glabrata strains. The isolation and identification of the isolates were done by standard mycological methods. Microbroth susceptibility tests were done in accordance with CLSI microdilution method (M27A-2). MICs were read at both 24 and 48 hours. At 24 h, MIC range, MIC50 and MIC90 values for amphotericin B were 0.5-4 micorg/ml, 2 microg/ml and 4 microg/ml, respectively. At 48 h, MIC range, MIC50 and MIC90 values for amphotericin B were 2-4 microg/ml, 4 microg/ml and 4 microg/ml respectively. At 24 h, 97% of the isolates were susceptible (S) and 3% were dose-dependent susceptible (S-DD) to fluconazole. None of the isolates were resistant (R) to fluconazole at this time point. At 48 h, 94% of the isolates were S, 5.2% were S-DD and 0.8% were R to fluconazole. At 24 h, 20.9% of the isolates were S, 73.1% were S-DD and 6% were R to itraconazole. At 48 h, 0.8% of the isolates were S, 62.7% were S-DD and 36.5% were R to itraconazole. These results suggest that although C.glabrata strains that were isolated in our hospital were rarely resistant to fluconazole, resistance rate to itraconazole is relatively high. Most of the isolates that are resistant to itraconazole remain susceptible to fluconazole.