COMPARISON OF IN-VITRO ACTIVITIES OF THE NEW TRIAZOLE SCH56592 AND THE ECHINOCANDINS MK-0991 (L-743,872) AND LY303366 AGAINST OPPORTUNISTICFILAMENTOUS AND DIMORPHIC FUNGI AND YEASTS

The in vitro antifungal activities of SCH56592, MK-0991, and LY303366 against 83 isolates of Acremonium strictum,Aspergillus flavus, Aspergi llus fumigatus, Aspergillus terreus, Bipolaris spp., Blastomyces derma titidis, Cladophialophora bantiana, Fusarium oxysporum, Fusarium solan i, Histoplasma capsulatum, Phialophora spp., Pseudallescheria boydii, Rhizopus arrhizus, Scedosporium prolificans, and Sporothrix schenckii were compared. The in vitro activities of these agents against 104 iso lates of yeast pathogens of Candida spp,, Cryptococcus neoformans, and Trichosporon beigelii were also compared, MICs mere determined by fol lowing a procedure under evaluation by the National Committee for Clin ical Laboratory Standards (NCCLS) for broth microdilution testing of t he filamentous fungi (visual MICs) and the NCCLS M27-A broth microdilu tion method for yeasts (both visual and turbidimetric MICs), The in vi tro fungicidal activity of SCH56592 was superior (minimum fungicidal c oncentrations [MFCs], 0.25 to 4 mu g/ml for 7 of 18 species tested) to those of MK-0991 and LY303366 (MFCs, 8 to >16 mu g/ml for ail species tested) for the molds tested, but the echinoeandins had a broader spe ctrum of fungicidal activity (MFCs at which 90% of strains are inhibit ed [MFC(90)s], 0.5 to 4 mu g/ml for 6 of 9 species tested) than SCH565 92 (MFC(90)s, 0.25 to 8 mu g/ml for 4 of 9 species tested) against mos t of the yeasts tested. Neither echinocandin had in vitro activity (MI Cs, >16 mu g/ml) against C. neoformans and T. beigelii, while the SCH5 6592 MICs ranged from 0.12 to 1.0 mu g/ml for these two species. The M ICs of the three agents for the other species ranged from <0.03 to 4 m u g/ml. These results suggest that these new agents have broad-spectru m activities in vitro; their effectiveness in the treatment of human m ycoses is to be determined.