Evaluation of the disk-diffusion method to determine the in vitro efficacy of terbinafine against subcutaneous and superficial mycoses agents Avaliação do método de disco-difusão para determinação da eficácia da terbinafina in vitro em agentes de micoses superficiais e subcutâneas*

BACKGROUND: Superficial and subcutaneous mycoses have a high prevalence and, often, chronic evolution. Therefore, they need extensive treatment with topic and/or systemic antifungal agents. Azoles and alilamines (terbinafine) are first-choice drugs to treat human and animal infections. Thus, evaluation of the efficacy of these drugs is important for a successful treatment. However, there are few studies that evaluate the in vitro activity of antifungal agents. OBJECTIVE To evaluate the in vitro efficacy of terbinafine activity against filamentous fungi and yeasts that cause mycoses. METHOD The in vitro activity of terbinafine (0.125-100μg) against 10 fungi species was evaluated by the disk-diffusion and microdilution/reference methods to determine the Minimum Inhibitory Concentration (MIC). RESULTS We found a high susceptibility to terbinafine in: T. rubrum, M. gypseum, T. mentagrophytes, T. tonsurans, M. canis, C. carrionii and E. floccosum (halo ≥ 40mm with 0.125μg disk). S. hyalinum and C. parapsilosis were considered susceptible, but less than the others. Fusarium spp. showed the lowest susceptibility (halo=12mm with 2μg disk; MIC 8μg/mL). CONCLUSIONS The results of this research confirm previous findings about the efficacy of terbinafine. The drug was shown to be highly effective to treat dermatophyte infections. The disk-diffusion method was easy to use and is a suitable technique for routine use in clinical laboratories.