In vitro susceptibility of nondermatophyte molds isolated from onycomycosis to antifungal drugs.

Despite many advances in antifungal drug development and therapy, onychomycosis due to nondermatophyte molds (NDM) remains difficult to treat. Using a reference microdilution method (CLSI M38-A), the antifungal susceptibility to bifonazole, ciclopiroxolamine, fenticonazole, itraconazole, ketoconazole, miconazole, terbinafine and tioconazole of 64 molds isolated from toenail onychomycosis was studied. All the strains showed good susceptibility to ciclopiroxolamine. Aspergillus had excellent susceptibility to itraconazole followed by miconazole, ketoconazole, tioconazole, fenticonazole and terbinafine. The isolated species had variable susceptibility to bifonazole. Scopulariopsis had wide MIC ranges for all antifungal drugs tested except ciclopiroxolamine. Fusarium and Acremonium had reduced susceptibility to antifungal drugs tested. Nevertheless, some strains show low MICs for ketoconazole, miconazole and tioconazole.Studies to evaluate in vitro susceptibility testing using CLSI methods for NDM onychomycosis should be undertaken.