Antifungal resistance and clinical significance in small animals

Abstract

Fungal diseases have risen in conjunction with the increasing number of immunosuppressive diseases in human and animal populations. Despite the introduction of new antifungal agents in recent years, the incidence of fungal infections continues to increase, and subsequently, the prevalence of resistance to these drugs is remarkably increased, posing significant health concerns. While antifungal drug resistance is of great importance in human medicine, especially against Candida spp., there are few studies about antifungal resistance in veterinary medicine. Indeed, several fungal infections include blastomycosis, candidiasis, coccidiomycosis, cryptococcosis, dermatophytosis, histoplasmosis, and Malassezia spp. infections have been reported in dogs and cats. Several antifungal drugs such as polyenes, azoles, pyrimidines, echinocandins, and allylamines have been encountered in feline and canine medicine. However, the desired success could not be obtained from the treatments applied in various cases in recent years due to antifungal resistance. This review aimed to emphasize the main common fungal infections in dogs and cats and the role of developing resistance against antifungal agents on treatment failures. Additionally, we discussed the mode of action of antifungal drugs, mechanisms of resistance, and factors that contribute to the emergence of resistance. In this context, monitoring of antifungal resistance in veterinary clinics and animal facilities by veterinarians and ther animal health authorities is recommended.