Avaliação clínica e ecoepidemiológica de leveduras de interesse médico

Abstract

The incidence of invasive fungal diseases has increased worldwide with Cryptococcus spp and Candida spp. Several fungi capable of causing human pathologies are environmental species whose pathogenicity evolved from the strategies developed in the stress environment. Objectives: To carry out a clinical and ecoepidemiological evaluation of yeast isolates of medical interest. Material and Method: Clinical samples of CSF obtained from patients with HIV were analyzed for the presence of Cryptococcus spp. The isolates were identified by biochemical characteristics, with subsequent genetic analysis by the RAPD technique for phylogenetic comparison. The antifungal susceptibility profile (fluconazole, itraconazole, amphotericin-B and 5-fluorocytosine) was evaluated for all samples using the microdilution technique. Environmental investigation in trees and feces of broilers was performed to determine the presence of yeasts of medical interest, with possible phylogenetic correlation to the clinical samples. These samples were also evaluated for the antifungal susceptibility profile, however with the disc diffusion technique. Results: Forty Cryptococcus spp isolates were obtained from 35 patients, 39 of whom were identified as C. neoformans and 1 with C. gattii. Five patients had sequential isolates (each with two isolates). Thirty-six (90%) belonged to serotype A, 7.5% to AD serotype and 2.5% to serotype B. RAPD analysis showed 6 groups with 13 subgroups, with a high coefficient of similarity. Most isolates were considered sensitive to the antifungal agents tested. Three clinical isolates presented colonies with late production of the enzyme phenoloxidase, adding to these samples the quantification analysis of the enzyme phenoloxidase and genetic analysis using restriction enzymes and electrophoresis. No change was found in the genetic pattern with phenotypic characteristics in these samples. Four hundred samples of decomposing material were analyzed in the period from 2015 to 2016, with isolation of C. tropicalis, C. albicans, C. krusei, C. glabrata, C. parapsilosis, C. guilliermondii and C. laurentii. High percentage of the samples showed resistance to azoles. Samples of feces of broiler chicken totaled 180, with a higher percentage of isolation of non-albicans species. However, they had a high antifungal sensitivity profile. There was no isolation of Cryptococcus spp in the environmental samples, and it was not possible to perform a phylogenetic correlation with the environmental samples. Conclusion: Prioritizing ecoepidemiological studies are necessary to understand the ecosystem that the pathogenic fungi are inserted, contributing in the genetic-phenotypic understanding in the pathogenesis. This fact is essential for the implementation of diagnostic and therapeutic techniques, as well as preventive measures with an emphasis on disease prevention in the community.