VARIABILIDADE GENÉTICA E SUSCEPTIBILIDADE A ANTIFÚNGICOS DE CEPAS DE Cryptococcus spp. NO ESTADO DE MATO GROSSO DO SUL

• Ano de defesa: 2024
• Autor(a) principal: LISANDRA SIUFI DE ARAUJO
• Orientador(a): Marcia de Souza Carvalho Melhem
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Fundação Universidade Federal de Mato Grosso do Sul
• País: Brasil
• Palavras-chave em Português: Criptococose. Meningite criptocócica. Variação genética. Fluconazol. Anfotericina B. Farmacorresistência fúngica.
• Link de acesso: https://repositorio.ufms.br/handle/123456789/11468

Cryptococcosis is a systemic mycosis caused by Cryptococcus spp, a yeast that is sometimes opportunistic, with meningoencephalitis being the most frequent manifestation. Due to the different characteristics of the molecular types of cryptococcosis agents, it is necessary to expand this knowledge in order to guide less empirical treatments. The aim of this study was to characterize strains of cryptococcosis agents obtained between 2002 and 2022 from regions in the state of Mato Grosso do Sul (MS), determine the occurrence of resistance phenotypes and assess their genetic variability. The data contained in the test requisitions was compiled: year, origin and type of biological sample. The genus identification of the isolates was previously carried out using conventional microbiology techniques and biochemical tests such as microcultivation on slides, phenol-oxidase production on Niger agar, cultivation on Canavanine, glycine and bromothymol blue (CGB) medium and auxanogram (assimilation of sugars - Phoenix® equipment). The sensitivity profile was determined by broth microdilution using the European Committee on Antimicrobial Susceptibility Testing (EUCAST) method with the antifungals: amphotericin B, fluconazole and voriconazole. To confirm the species and genetic variability, the isolates were identified by matrix-assisted laser desorption ionization (MALDI-TOF MS), and the protein spectra were analyzed in two databases: Bruker Daltonics and Mass Spectrometry Identification- MSI V2. Of the 127 isolates studied, all were classified at species level, with 113 (88.98%) being C. neoformans and 14 (11.02%) C. gattii. The genotyping carried out on 98 isolates allowed adequate identification (score A) for 58 isolates (59.1%). The results draw attention to 44 AD hybrid VNIII genotypes (44.9%). The minimum inhibitory concentration (MIC) was determined for the 127 isolates; no strains resistant to amphotericin B (clinical cut-off point 1 mg/L) or non-wild to voriconazole (epidemiological cut-off point, 0.5 mg/L for C. neoformans) were identified. For fluconazole, there are no defined clinical or epidemiological cut-off points, and MIC values below 16 mg/L characterized sensitive strains. The expected higher prevalence of C. neoformans (114; 89.8%) over C. gattii (13; 10.2%) in the Mato Grosso region is confirmed. The notable frequency of hybrid genotypes stands out as an unprecedented finding that requires confirmation by gold standard methodology. The complete sensitivity of the cryptococcosis agents in the Mato Grosso do Sul region is in line with previous data from the Midwest region and Brazil. Keywords: Criptococcosis. Cryptococcal Meningitis. Genetic Variation. Fluconazole. Amphotericin B. Fungal drug resistance.