Insights into Candida tropicalis virulence factors

• Author(s): Negri, M. ; Henriques, Mariana ; Silva, Sónia Carina ; Svidzinski, T. ; Azeredo, Joana ; Oliveira, Rosário
• Date: 2011
• Persistent ID: https://hdl.handle.net/1822/17242
• Origin: RepositóriUM - Universidade do Minho
• Document Type: Other
• Language: English
• Contributor(s): Universidade do Minho

Description

Candida tropicalis is a common nosocomial species related to candidemia and candiduria. Several virulence factors seem to be responsible for C. tropicalis infections, which lead to high mortality. Adhesion to surfaces (medical devices and host cells) and biofilm formation are considered important factors that contribute to the development of candidosis. Therefore, adhesion to urinary catheters and biofilm formation were assessed in an optimized in vitro flow model, using silicone and latex urinary catheters and artificial urine (AU). Moreover, biofilm matrices were also evaluated in terms of proteins and carbohydrates. Regarding adhesion to biotic surfaces, the interaction of C. tropicalis with host cells was determined using three different human epithelial cell lines: TCC-SUP (urinary bladder); HeLa (cervical carcinoma) and Caco-2 (colorectal adenocarcinoma). Specifically, the degree of human cells damage and activity reduction induced by C. tropicalis adhesion and the role of Candida tropicalis aspartyl proteinases (SAPT) genes expression were assessed. Additionally, the influence of C. tropicalis biofilm cells with different ages (24 - 120 h) on TCC-SUP cells integrity was also studied. Another important Candida factor is its resistance to antifungal agents, which was also assessed and related with the expression of enzymes and hyphae formation. In summary, C. tropicalis strains were able to form biofilms in AU, in static or dynamic mode, although, with differences among strains. It is important to emphasize that human cells response to C. tropicalis adhesion, as well as SAPs production, is strain and cell line dependent. Additionally, it should be highlighted that C. tropicalis cells detached from biofilms are able to colonize human cells and cause injury and reduction of metabolic activity. In addition SAPT3 was highly expressed compared to other SAPT genes. Therefore, it should be pointed out that C. tropicalis presented a set of different virulencefactors that might be responsible for its high degree of infection.