[In vitro activity of fluconazole, voriconazole and posaconazole against Candida spp]

Abstract

Voriconazole and posaconazole are two new triazoles with broad-spectrum antifungal activity. The in vitro activity of these agents was compared with that of fluconazole against 113 clinical isolates of Candida spp. exhibiting a wide range of MICs for fluconazole (< or =0.125 to >64 mg/l). They included 22 C. albicans isolates, 22 C. glabrata, 20 C. tropicalis, 15 C. dubliniensis, 13 C. parapsilosis, 13 C. krusei, 4 C. lusitaniae, 3 C. guilliermondii and 1 C. famata. MICs were determined by broth microdilution test performed according to the National Committee for Clinical Laboratory Standards' M27-A document. Voriconazole and posaconazole were quite active against all Candida spp. isolates, with MIC(90) of 0.25 and 0.5 mg/l, respectively. Fluconazole MIC(50) and MIC(90) were 1 and 32 mg/l. Voriconazole and posaconazole showed in vitro activity against fluconazole-susceptible and -resistant Candida isolates. Higher voriconazole and posaconazole MICs were observed in isolates exhibiting higher fluconazole MICs (>/=16 mg/l) than in those of fluconazole-susceptible isolates (MIC(90) for voriconazole and posaconazole in the fluconazole-resistant isolates were 0.5 mg/l versus 0.06 mg/l for voriconazole and 0.25 mg/l for posaconazole in the fluconazole-susceptible strains). C. dubliniensis was the most susceptible species, and voriconazole the most active antifungal agent against all Candida spp. tested.