Antifungal susceptibility of Candida albicans biofilm on Poly(methyl-methacrilate)

Objective: The aim of this study was to evaluate the antifungal susceptibility of Candida albicans biofilm developed on Poly(methyl-methacrilate) resins surfaces and compare with their planktonic counterpart. Methods: susceptibility tests (MIC, MFC and Time Kill) of two different Candida species (Candida albicans ATCC 90028 and Candida albicans SC5314) were used to determine the MIC concentration for Fluconazole (FLU) and Nystatin (NYS). Biofilm of the two species were allowed to develop on PMMA surface. Surface roughness (SR) and surface free energy (SFE) of PMMA specimens were previously measured. After 48 hours development, biofilms were exposed to both antifungal during 24 hours at MIC, 10xMIC, 100xMIC and 1000xMIC concentration. Biofilm activity were measured by XTT assay. Confocal images were used to measure biomass, average thickness, biofilm roughness, diffusion and the of LIVE/DEAD cells proportion in the different biofilm development stages. Cell counts were used to estimate the number of cells in those biofilms. Results: Biofilms susceptibility for NYS were detected at 100xMIC and 1000XMIC for FLU (P<0.05). Both species showed different susceptibility behavior for each antifungal. Decreased XTT readings were detected after drug exposure. Biofilm structures were affected by both drugs. Conclusion: It can be concluded that biofilms decreased the susceptibility to antifungal compared to their planktonic counterparts. Supported by CAPES and CNPq.