Micobiota leveduriforme oral de cães: identificação fenotípica e proteômica

The increasing interaction between humans and animals facilitates the transmission of microorganisms, making the study of the oral mycobiota of dogs increasingly relevant, especially due to the development of diseases caused by fungi such as Candida auris, Malassezia pachydermatis, and Cryptococcus spp., which require effective diagnostic methods. Although phenotypic identification is widely used, it has limitations that can be overcome by advanced technologies such as the proteomic MALDI-TOF technique. In this context, the objective of this study was to isolate yeast-like fungi from the oral cavity of dogs, perform phenotypic and proteomic identification of the isolates, and compare the effectiveness of these methodologies. For this purpose, samples were collected from 38 dogs in veterinary clinics in Seropédica and Itaguaí (Rio de Janeiro, Brazil), as well as at the Veterinary Hospital of the Federal Rural University of Rio de Janeiro, resulting in 46 yeast isolates. The samples were plated on Sabouraud agar with chloramphenicol, and the isolates were identified through macromorphological, micromorphological and biochemical tests, sugar assimilation and fermentation assays, and proteomic identification using MALDI-TOF equipment. Among the 37 isolates compared, 11 showed positive species correspondence between the phenotypic and proteomic methods. In cases such as Geotrichum spp. and Rhodotorula spp., proteomic identification proved less efficient, reinforcing the choice of the phenotypic method as the most suitable for classifying the isolates. This preference is also confirmed for predominant yeasts such as Candida spp. and Malassezia spp., demonstrating the phenotypic method as a reliable tool for characterizing the oral mycobiota of dogs, given the prevalence of these genera in the population of cultivable microorganisms. Of the 37 yeasts tested proteomically, 27 were identified as the genus Candida, with 21 confirmed by phenotypic identification, highlighting the potential of the proteomic technique as an aid in identifying these microorganisms. Although the proteomic technique is quick, it still requires improvements to identify non-Candida yeasts, making it useful as a complementary diagnostic tool. On the other hand, phenotypic identification proved to be effective and reliable for characterizing the yeasts in the oral cavity of dogs.