Antifungal susceptibility and genotypical pattern ofMicrosporum canisstrains

Abstract

Dermatophytes are a group of fungi that are capable of invading keratinized tissues of humans and other animals. Antifungal susceptibility analysis and genetic studies by random amplification of polymorphic DNA (RAPD), have been used to detect polymorphism as well as determining the possible resistance of dermatophytes to antifungals. The aim of this study was to evaluate the possible correlation between the antifungal susceptibility and genotypical pattern of Microsporum canis strains isolated in dogs and cats with dermatophytosis in Northeast Brazil. The antifungal susceptibility study was conducted using the broth microdilution test with griseofulvine, ketoconazole, itraconazole, and fluconazole. The genotypical analysis was performed using the RAPD method. The antifungal susceptibility analysis showed that all the strains of M. canis analyzed (n = 22) were sensitive to griseofulvine (0.25 µg/mL ≤ minimum inhibitory concentration (MIC) ≤ 1 µg/mL), ketoconazole (0.25 µg/mL ≤ MIC ≤ 2 µg/mL), itraconazole (0.25 µg/mL ≤ MIC ≤ 1 µg/mL), and fluconazole (1 µg/mL ≤ MIC ≤ 16 µg/mL). The RAPD results showed that all analyzed strains are genetically similar. Thus, based on antifungal susceptibility analysis and RAPD data, a possible correlation can be shown between the antifungal susceptibility and the genotypical pattern of the strains of M. canis from Northeast Brazil.Key words: Microsporum canis, antifungal susceptibility testing, RAPD.