Dermatófitos em cães e gatos e resistência a antimicrobianos

Abstract

Dermatophytosis is a superficial fungal infection of keratinized tissues such as hair, nails and the stratum corneum of the epidermis. In dogs and cats, it is commonly caused by dermatophytes of the genera Microsporum, Nannizzia and Trichophyton. Its prevalence in small animals is still unknown, but it is estimated that it affects about 4-15% of canines and up to 20% of felines. In addition to the relevance of dermatophytosis in animal health, it is an anthropozoonosis, which affects about 40% of the human population, and currently is a public health major problem, since it is widely disseminated in urban centers. In view of their easy dissemination, sites with agglomeration of animals are potentially contaminated. Therefore, animal shelters turn the control of this disease a challenge. In this study, 150 asymptomatic animals from the Municipal Shelter of Varginha- MG were analyzed, where 7.3% were positive for dermatophytes. Among those, 4% were canines and 14% felines. Microsporum canis was the only species of dermatophyte isolated in the present study. The isolates obtained from the studied populations, as well as isolates belonging to the Database of Microorganisms of the DMV/UFLA totaling 28 isolates, were submitted to susceptibility tests to antifungals by means of the diffusion technique in discs. Four distinct drugs were evaluated: ketoconazole; itraconazole; clotrimazole and fluconazole. It was observed that ketoconazole was the most efficient drug to inhibit growth of isolates, demonstrating antimicrobial action against 53.57% of the samples evaluated, followed by clotrimazole 39.28% of susceptible isolates. Itraconazole and fluconazole showed low antimycotic action against the tested isolates, with 85.71% of the samples resistant to itraconazole and 96.43% to fluconazole. The study pointed out the existence of asymptomatic carriers in shelter animals, demonstrating that these may be important reservoirs for dermatophytes of importance in public health and a high index of resistance of the isolates to the drugs evaluated, which may be associated with the misuse of antifungal agents. It is necessary to surveillance and further investigations in relation to resistant dermatophytes, as they are a threat to collective health, considering their zoonotic importance and the high levels of resistance pointed out by the present study.