[In vitro activities of antifungal drugs against clinical isolates of Trichophyton tonsurans].

To determine drug susceptibility of Trichophyton tonsurans endemic in Japan, in vitro MICs of antifungal drugs against a total of 10 clinical isolates of T. tonsurans collected from dermatophytosis patients were measured by the agar dilution method and the broth microdilution method. The agar dilution method was not appropriate as the growth of T. tonsurans on the agar medium was too slow to determine drug activity, while the broth microdilution method was thought to be an appropriate method for this study. The MIC90 values determined by the broth microdilution method for terbinafine, itraconazole, miconazole and ketoconazole were 0.013, 0.1, 0.8 and 0.4 microg/ml, respectively. Meanwhile, the MIC90 values of lanoconazole and luliconazole, known to be antifungal drugs potent against dermatomycosis, were 0.00078 and 0.00039 microg/ ml, respectively. The drug susceptibility of these T. tonsurans isolates to the aforementioned antifungal drugs was found to be on a similar level with that of T. mentagrophytes and T. rubrum, major causative agents of dermatomycosis. The results also demonstrated the strong antifungal activity of lanoconazole and luliconazole against T. tonsurans.