In vitro activity of caspofungin against fluconazole-resistant Candida isolates from patients with HIV infection

Abstract

Antifungal therapy for mucosal candidiasis caused by fluconazole-resistant Candida species is problematic. The aim of this study was to investigate the in vitro activity of caspofungin against Candida strains with reduced susceptibility to fluconazole isolated from HIV-infected patients. The in vitro activity of caspofungin was assessed in 28 fluconazole-resistant Candida isolates obtained from the oral cavity of a cohort of 174 consecutive HIV-infected patients. Minimum inhibitory concentrations (MICs) were determined by a standardized broth microdilution method, as recommended by the NCCLS. Overall, caspofungin MICs ranged from < or = 0.06 microg/ml to 1 microg/ml. MICs at which 50% (MIC50) and 90% (MIC90) of isolates were inhibited were 0.25 microg/ml and 0.5 microg/ml, respectively. MICs ranged from < or = 0.06 microg/ml to 0.5 microg/ml for Candida albicans (n = 11), and < 0.06 microg/ml to 1 microg/ml or Candida glabrata (n = 11). MICs for the two strains of Candida krusei were 0.125 microg/ml and 1 microg/ml. The range of MICs for Candida tropicalis and Candida inconspicua strains was 0.25 microg/ml to 0.5 microg/ml. Caspofungin was very active in vitro against a variety of fluconazole-resistant Candida strains recovered from a clinical cohort of HIV-infected patients. The MIC50 values and MIC ranges were slightly higher for Candida glabrata than for Candida albicans.