Análise filogenética de isolados orais de Candida spp. em Salvador, Bahia, Brasil.

Abstract

Introduction: Fungal infections are directly linked to severe cases and mortality worldwide, specifically those caused by fungi of Candida species. The primary pathogenic fungus affecting humans is Candida albicans, predominantly found in immunosuppressed individuals. However, non-albicans species (NCAs) have become increasingly prevalent. The species within this genus exhibit high genetic variability and antifungal resistance, making infections more frequent and treatments more challenging. Molecular and phylogenetic analyses, involving the Internal Transcribed Spacer (ITS) region, have aided in the exploratory research of variability factors and antifungal resistance in these microorganisms, aiming to elucidate these unknowns and assist in treatment strategies as well as the containment of outbreaks globally. Objective: Thus, the objective of this study is to phylogenetically analyze the Candida spp. species found in the oral cavity of humans with denture stomatitis. Materials and Methods: Twenty-five samples of Candida species, provided by the Microteca de Saúde (Health Micro-library) of GPSA/ICS/UFBA, were subjectedto morphological identification and subsequent molecular assays. After reading, fungal DNA extraction and polymerase chain reaction (PCR) were performed. Sequencing was conducted, and the sequences were submitted to the Basic Local Alignment Search Tool (BLAST) and to the GenBank of the National Center for Biotechnology Information (NCBI) for the construction of phylogenetic trees based on Maximum Likelihood and Bayesian Inference. Results: The evaluation grouped most of the PACs into well-defined and monophyletic clades in both phylogenetic methods, with the exception of the Bayesian analysis of the 28S fragment of C. albicans. PAC1 (C. dubliniensis), PAC17 (C. albicans), and PAC18 (C. albicans) stood out by presenting distinct genetic profiles and being more evolutionarily distant from the other samples when compared in a tree that included all species. Conclusion: There is a high level of intra specific genetic homogeneity among the oral Candida samples in Salvador-BA, with possible recent ancestors forming well-defined monophyletic clades. Furthermore, some distinct lineages exhibited significant genetic differences from the other samples, suggesting adaptation to the environment.