Fatores de virulência in vitro de leveduras isoladas da cavidade oral de cães

Abstract

Periodontopathies are the most recurrent infectious diseases in dogs, being mainly described by the involvement of bacterial agents. Several studies have addressed the bacterial components of the dog's oral cavity. However, the same is not seen for yeasts, even though they are already described as part of the oral microbiota, which may promote primary disorders or establish secondary conditions. It is known that the animal’s general condition can have several consequences as a result of oral affections, such as feeding difficulties and the possibility of ascending infections, with possible systemic aggravation. Furthermore, the closer contact between dogs and humans makes the occurrence of bite wounds more frequent, which increases the importance of knowing the microorganisms present in the dog’s oral cavity to elucidate infections of this origin. Fungal infection manifestation depends on several factors, including immunosuppression conditions and microbiological imbalance with a consecutive decrease in the competitive activity of commensal microorganisms. The need to elucidate the pathogens involved in oral microbiota disorders in dogs is raising. To improve knowledge in this area, saliva samples were collected from different sites in the oral cavity of dogs, using toothbrushes previously deposited in tubes with sterile saline for further processing and isolation of microorganisms. This study sought to identify yeast components from the healthy and injured oral cavity of dogs and to evaluate in vitro virulence factors (protease, phospholipase, and DNAse) of these unicellular microorganisms. The study aimed to, in addition to contributing to animal welfare and public health, the identification of yeast components of the oral cavity of dogs, comparison of healthy and injured oral microbiota, in vitro virulence evaluation of the isolates, and knowledge support in the therapeutic clinical treatment of affections of that origin. For this, the present work counted on samples of 54 dogs, 27 of them without lesions in the oral cavity, belonging to Group 1, and 27 with lesions in the oral cavity, belonging to Group 2. A total of 68 samples with yeasts were obtained, composed of 33 yeasts from Group 1 (48.53%) and 35 from Group 2 (51.47%). Those were identified as Malassezia pachydermatis (n= 24 / 35,29%), Geotrichum spp. (n= 11/ 16,18%), Candida glabrata (n= 6 / 8,82%), Complexo Candida albicans (n= 5 / 7,35%), Rhodotorula spp. (n = 5 / 7,35%), Candida lusitaniae (n= 4 / 5,88%), Candida krusei (n= 4 / 5,88%), Candida tropicalis (n= 3 / 4,41%), Candida famata (n= 2 / 2,94%), leveduras negras (n= 2 / 2,94%) e Trichosporon spp. (n = 2 / 2,94%). Subsequently, 48 of these isolates were evaluated for virulence factors, being 87.5% (42/48) protease producers, 50% (24/48) of the strains with phospholipase enzymatic activity, and 72.92% (35/48) DNAse producers. There was no statistically significant difference in the production of protease, phospholipase, and DNAse between the groups of dogs without lesions and with lesions in the oral cavity