Z-oo2 Comparison of tyrosol's effect on Candida albicans and Candida glabrata in different stages of biofilm development

Objectives: The aim of this study was to compare the effect of tyrosol on Candida albicans and Candida glabrata in different stages of biofilm development (2, 48 and 96 h). Methods: Tyrosol was diluted in yeast inocula (107 cells/mL in artificial saliva) at 25, 50, 100 and 200 mM, and added to wells of 24-well plates containing the acrylic specimens. Then, the plates were incubated at 37 °C for 2 and 48 h. Moreover, tyrosol was applied to pre-formed biofilms (24-h old) twice a day for 1 min, during 3 days (totaling 96 h-old biofilms). Tyrosol efficacy was assessed by quantification of total biomass (TB), metabolic activity (MA) and colony forming units (CFUs). Data were analyzed by ANOVA and Holm-Sidak test (α = 0.05). Results: For adhesion assays (2 h), tyrosol promoted significant reductions in the TB, MA and CFUs of C. albicans , while for C. glabrata these reductions occurred only for CFUs in the group 200 mM tyrosol (p<0.001). Further, for 48 h-old biofilms grown in the presence of tyrosol, it was possible to note dose-dependents inhibitory effects for both Candida species. Regarding 96 h-old biofilms, tyrosol was more effective in reducing TB and MA on C. glabrata biofilms than on C. albicans. There were no reductions in CFUs at this stage. Conclusions: In summary, tyrosol showed better results on the less advanced stages of biofilm development. Thus, this compound has potential to contribute at preventing oral infections caused by Candida species. Acknowledgment : FAPESP (#2013/17767-2, 2013/10285-2 and 2013/03273-8)