Genetic characterisation of Candida albicans isolates from distinct clinical human samples and the clinical environment

• Autor(a) principal: Sampaio, Filipa Azevedo
• Data de Publicação: 2022
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10773/36438
• topic: Candida albicans; Whole genome sequencing; Polimorphisms; Antifungal resistance; Multilocus sequence typing; Gene ontology analysis; Loss of heterozygosity

Candida albicans is a commensal microorganism of the human normal microbiota, capable of turning pathogenic, and one of the leading causes of human fungal infections with mortality rates as high as 50%. Based on this problem, it is imperative to routinely characterize this pathogen, not only phenotypically but also genotypically, to identify the genomic traits responsible for disease, drug resistance, adaptability to ecological niches, and unravel the genetic diversity among distinct isolates. As so, in this study, a collection of 76 C. albicans strains collected from blood, vaginal and oral samples, and samples from medical devices was characterized by whole genome sequencing and bioinformatics analysis. Their genome sequence was explored to discriminate and epidemiologically contextualize strains globally, identify genes with single nucleotide polymorphisms (SNPs) and contribute to the knowledge on the C. albicans variome. The isolates genome analysis showed that one of the isolates had been misidentified as C. albicans, being C. glabrata. A higher number of SNPs than usual was identified, possibly due to the high number of homozygous SNPs. Genes with SNPs common to all isolates, with SNPs exclusive of isolates from each sample type, and with SNPs common to all isolates of each origin were identified. Often, the frequency of genes with missense SNPs involved in molecular functions and biological processes was significatively higher when compared to the reference strain frequency in those gene ontology sets.