Study on determining MIC of ketoconazole against dermatophyte by agar cylinder method

摘要

Standardized inocula, as a key to determing MIC of antifungal agents against pathogenic filament fungi, is still a technically difficult assay. Recently, we determined the MIC of Ketoconazole to 20 strins of dermatophyte with imporoved agar cylinder test and gained good results. Methods: dilute ketoconazole in solid medium in a 24--well cultural plate with ten twofold serial dilution, and standardized agar cylinders ar cut from the plate wells and filled with inocula of the dame size cut from petri dish of dermatophyte cultures. The MIC is evaluated at 28 deg C after 3 and 7 days' incubation. Results: the MIC range of Ketoconazole against 20 dermatophyte strains are 0.05-1.6mg/L, which is similar to that of microdilution method. Conculusion: the new technique is reliable, quick, and highly reproducible, especially can quantify the inocula accurately.