Head-to-Head Comparison of the Activities of Currently Available Antifungal Agents against 3,378 Spanish Clinical Isolates of Yeasts and Filamentous Fungi

<jats:title>ABSTRACT</jats:title> <jats:p> We have compared the activities of posaconazole and other currently available antifungal agents against a collection of 3,378 clinical isolates of yeasts and filamentous fungi. A total of 1,997 clinical isolates of <jats:italic>Candida</jats:italic> spp., 359 of other yeast species, 697 strains of <jats:italic>Aspergillus</jats:italic> spp., and 325 nondermatophyte non- <jats:italic>Aspergillus</jats:italic> spp. were included. The average geometric means of the MICs of agents that were tested against <jats:italic>Candida</jats:italic> spp. were 0.23 μg/ml for amphotericin B, 0.29 μg/ml for flucytosine, 0.97 μg/ml for fluconazole, 0.07 μg/ml for itraconazole, 0.04 μg/ml for voriconazole, 0.15 μg/ml for caspofungin, and 0.03 μg/ml for posaconazole. Voriconazole and posaconazole were active in vitro against the majority of isolates, with resistance to fluconazole and itraconazole, and against <jats:italic>Cryptococcus neoformans</jats:italic> and other <jats:italic>Basidiomycota</jats:italic> yeasts. Posaconazole was the most active of antifungal agents tested against <jats:italic>Aspergillus</jats:italic> spp., with an average geometric mean of 0.10 μg/ml. It was active against <jats:italic>Paecilomyces</jats:italic> spp., <jats:italic>Penicillium</jats:italic> spp., <jats:italic>Scedosporium apiospermum</jats:italic> , and some black fungi, such as <jats:italic>Alternaria</jats:italic> spp. Multiresistant filamentous fungi, such as <jats:italic>Scedosporium prolificans</jats:italic> , <jats:italic>Scopulariopsis brevicaulis</jats:italic> , and <jats:italic>Fusarium solani</jats:italic> , were also resistant to voriconazole, caspofungin, and posaconazole. Amphotericin B and posaconazole were found to be active against most of the <jats:italic>Mucorales</jats:italic> strains tested. Posaconazole and currently available antifungal agents exhibit a potent activity in vitro against the majority of pathogenic fungal species. </jats:p>