In vitro efficacy of 5 antifungal agents against Candida parapsilosis, Candida orthopsilosis, and Candida metapsilosis as determined by time-kill methodology.

Killing activity of amphotericin B, fluconazole, voriconazole, posaconazole, and 5-fluorocytosine was determined against 6 Candida parapsilosis, 3 Candida orthopsilosis, and 4 Candida metapsilosis clinical isolates. After 24 h, 1 of 6 C. parapsilosis, 1 of 3 C. orthopsilosis, and 3 of 4 C. metapsilosis isolates were killed at 1 to 4 microg/mL (1-8x MIC) amphotericin B. The remaining isolates were killed by 2 to 4 microg/mL amphotericin B after 48 h. Fluconazole was fungistatic at > or =1x MIC (0.5-2 microg/mL) against C. parapsilosis and at > or =2x MIC (4-8 microg/mL) against C. orthopsilosis and C. metapsilosis isolates. Voriconazole inhibited C. parapsilosis at > or =1x MIC (0.015-0.12 microg/mL), but the other 2 species were inhibited only at 4 to 8x MIC (0.25-0.5 microg/mL). Against C. orthopsilosis and C. metapsilosis, posaconazole was fungistatic close to the MIC (0.03-0.06 and 0.015-0.03 microg/mL, respectively). Against C. orthopsilosis and C. metapsilosis, fluconazole and voriconazole, but not posaconazole, seem to be less active in vitro than against C. parapsilosis.