Virulence-associated phenotypes in clinical isolates of Candida albicans: biofilm production and candidalysin
Year: 2024
Type: dissertation
Abstract: Candida albicans is an opportunistic fungus responsible for different types of infections, from localized mucosal candidiasis to disseminated candidaemia. Biofilms and candidalysin are two of the virulence factors of C. albicans and give the fungus the ability to invade epithelia, to evade the immune system and to resist antifungals. The aim of this study was to assess the individual ability of 25 clinical isolates from 5 different infection sites, blood, oral, vaginal, medical devices and gastric, to form biofilms. The expression of the ECE1 gene in mature biofilms was also studied since this gene includes the sequence coding for candidalysin and is possibly involved in filamentation. Crystal violet, XTT assays and optical and scanning electronic microscopy were performed to characterise biofilms, and real-time PCR for gene expression analysis. We found that biofilm formation is strain-specific and that there are no statistically significant differences across niches. Biofilms are diverse in their biomass and structure. At 48h, the vaginal clinical isolates showed the highest diversity, while gastric infection and medical devices isolates demonstrated high similarity in their ability to form biofilm. The isolates were distributed according to a ranking of biofilm production capacity; according to that rank, 5 isolates are high biofilm producers, and 6 are low biofilm producers. The biofilm cycle revealed identical in all the isolates with a maximal biomass recorded at 48 h. No statistical relationship was found between biofilm-forming ability and ECE1 expression, in 48-hour mature biofilms. Although there are no statistical differences between isolates from different sites of infection, there is significant variability between different strains, proving important, as future work, the genomic profiling of these isolates.
Author: Silva, Leandro Filipe da Costa
Language: English
Subfield: Infectious Diseases
Field: Medicine
Domain: Health Sciences
Open Access status: green
OpenAlex ID: W7063055035