Resumo

Dermatophytes are a group of closely related parasitic fungi that have the capacity to invade keratinized tissue (skin, hair, and nails) of humans and animals. They are the primary causative agents of dermatophytoses, a major public health concern in some geographic regions. These fungi are divided into three genera Microsporum, Epidermophton, and Trichophyton, and have been shown to represent a homogeneous group of species with very low genetic diversity contrasting with high phenotypic heterogeneity. Based on their natural habitats, are classified as geophilic, zoophilic, and anthropophilic species. The higher incidence of infection is caused by the genera Trichophyton, being T. rubrum the most prevalent in human skin and nail infections due to its ability to infect and evade host defenses. Because of the severity and longevity of the disease and its refractivity, aspects involved in the resistance of dermatophytes to antifungals on the market and survival in the host environment are gaining importance. During growth in keratin as the only nutrient source in conditions that mimetize the infection, and in the presence of two nonstructurally related drugs, Amphotericin B and Itraconazole, we observed an over-expression of two genes encoding ATP-binding cassette (ABC) transporters, mdr1 and mdr2, in three species of the Trichophyton genera (T. rubrum, T. equinum, T. tonsurans) suggesting their participation in the toxicant efflux system, contributing to the mechanisms of antifungal drug resistance. The transcriptional profile indicates that these genes are regulated by the pH since the expression increased during alkalinization reinforcing the importance of them in the maintenance of the infection. Our results suggest that these two genes could be involved in the antimicrobial treatments failure in dermatophytes, being possibly potential antifungal drug targets, and essential to have a full understanding about the mechanisms of fungal-host interactions.