Effect of media composition and in vitro activity of posaconazole, caspofungin and voriconazole against zygomycetes

Objectives: The effect of different media and composition on the in vitro activity of posaconazole, caspofungin and voriconazole against 59 zygomycetes species was determined. Methods: The media tested were RPMI 1640 medium with and without 2% glucose, antibiotic medium 3 (AM3) with and without 2% glucose, and high resolution (HR) medium. Results: Posaconazole was significantly more active than caspofungin and voriconazole, both in RPMI 1640 medium with 2% glucose and in HR medium. Adding glucose improved the determination of end points, but had only minor influence on the MICs. MICs evaluated in AM3 were lower than in RPMI 1640 medium or HR medium. Conclusions: The in vivo effect of posaconazole in zygomycosis needs further evaluation.