The influence of subinhibitory concentrations of fluconazole and amphotericin b in the biofilm formation of Candida albicans and Candida dubliniensis

Abstract

The most common antifungal agents used to treat candidiasis are fluconazole and amphotericin B. As biofilm formation of Candida species is one of the steps in oral pathogenesis it is very important to study the evolution of biofilm formation in the presence of subinhibitory concentrations of antifungal agents, which are commonly used as therapy in immunossupressed patients. Acrylic was the surface selected because it is the most used material to produce prosthetic devices and is responsible for the major contaminations in the mouth. Biofilm formation was performed with two different strains of each Candida species, C. albicans and C. dubliniensis. Strains were grown and allowed to form biofilm in artificial saliva growth medium supplemented with subinhibitory concentrations of fluconazole and amphotericin B. The biofilm formation along the time was analysed in terms of total biomass (using crystal violet staining) and activity (through the formation of formazan salts by XTT). The results showed that there were differences in the amounts of biofilms formed by the two species and even between the strains. The effect of subinhibitory concentrations of the antifungal agents on biofilm formation was not notorious. As general conclusion, biofilm formation in the presence of subinhibitory concentrations of the antifungal agents is either strain or species dependent.