In vitro activity of the new echinocandin antifungal, MK-0991, against common and uncommon clinical isolates of Candida species

A broth macrodilution method, performed as recommended by the National Comm ittee for Clinical Laboratory Standards, was used for comparative testing o f the new echinocandin antifungal agent MK-0991 and fluconazole against 50 yeast isolates belonging to 12 species of Candida. MK-0991 was shown to be highly effective against both fluconazole-susceptible and -resistant Candid a spp., yielding minimum inhibitory concentrations ranging from less than o r equal to 0.19 to 0.78 mu g/ml. Fungicidal activity was exerted at less th an or equal to 1.5 mu g/ml for 73% of the isolates tested. This study sugge sts that MK-0991 has significant potential for clinical development.