Phenotypic and genotypic detection of Candida albicans and Candida dubliniensis strains isolated from oral mucosa of AIDS pediatric patients

• Published in: Revista do Instituto de Medicina Tropical de São Paulo
• Main Authors: Harisson Oliveira Livério, Luciana da Silva Ruiz, Roseli Santos de Freitas, Angela Nishikaku, Ana Clara de Souza, Claudete Rodrigues Paula, Carina Domaneschi
• Format: Article in Journal/Newspaper
• Language: English
• Published: Universidade de São Paulo (USP)
• Subjects: Candida dubliniensis; Candida albicans; Children; HIV/AIDS Phenotypic and genotypic methods; Arctic medicine. Tropical medicine; RC955-962; Infectious and parasitic diseases; RC109-216; Arctic
• Online Access: https://doi.org/10.1590/s1678-9946201759014; https://doaj.org/article/ff0a8cb04a914bd6b2b1f7e4d4598cb1

ABSTRACT The aim of this study was to assess a collection of yeasts to verify the presence of Candida dubliniensis among strains isolated from the oral mucosa of AIDS pediatric patients which were initially characterized as Candida albicans by the traditional phenotypic method, as well as to evaluate the main phenotypic methods used in the discrimination between the two species and confirm the identification through genotypic techniques, i.e., DNA sequencing. Twenty-nine samples of C. albicans isolated from this population and kept in a fungi collection were evaluated and re-characterized. In order to differentiate the two species, phenotypic tests (Thermotolerance tests, Chromogenic medium, Staib agar, Tobacco agar, Hypertonic medium) were performed and genotypic techniques using DNA sequencing were employed for confirmation of isolated species. Susceptibility and specificity were calculated for each test. No phenotypic test alone was sufficient to provide definitive identification of C. dubliniensis or C. albicans, as opposed to results of molecular tests. After amplification and sequencing of specific regions of the 29 studied strains, 93.1% of the isolates were identified as C. albicans and 6.9% as C. dubliniensis. The Staib agar assay showed a higher susceptibility (96.3%) in comparison with other phenotypic techniques. Therefore, genotypic methods are indispensable for the conclusive identification and differentiation between these species.