INVESTIGATION OF THE EFFECTIVENESS OF TYROSOL ON CANDIDA TROPICALIS HYPHAL WALL PROTEIN (HWP1)

Abstract

Microorganisms of the genus Candida are fungal pathogens that cause mucosal and invasive infections in immunocompromised individuals. In particular, C. tropicalis is one of the most frequently isolated species from candidemia and candiduria after C. albicans. Biofilm formation is a very important virulence factor regulating Candida pathogenesis, and combating biofilm-related infections is very difficult. Tyrosol (2-[4-hydroxyphenyl] ethanol), a fungal quorum sensing molecule, induces germ tube formation and hyphal development in the early and intermediate stages of biofilm formation, and when added exogenously to the medium, it reduces the biofilm in a concentration-dependent manner. However, the effectiveness of tyrosol on fungal pathogens has not yet been fully elucidated. Hyphal wall protein (HWP1) is an important adhesin protein found in some Candida species and is required for biofilm formation in vivo. In this study, the antimicrobial activity of tyrosol on a clinical Candida isolate (C. tropicalis 1660) was investigated microbiologically, and its activity on the fungal cell wall was examined under a transmission electron microscope (TEM) using the immunold labeling technique. The minimum inhibitory concentration (MIC) value of tyrosol was determined as 18.75 µg/mL by broth microdilution test. Our TEM results revealed that the HWP1 protein, which was localized on the cell wall in the control group, dispersed along with the damage in the cell after tyrosol application. The damaging effect of exogenous tyrosol on cell ultrastructure and the reducing effect on HWP1 protein should also be taken into consideration in antibiofilm activity studies.