Effect of fatty acids on biofilm formation, oxidative stress and antifungal susceptibility of Candida albicans and Candida dubliniensis

[摘要] English: Candida albicans and C. dubliniensis are commensals of the gastrointestinal andgenitourinary tract in healthy individuals. However, in diseased individuals they cancause superficial infections to deep seated mycoses. Both species form mycelialnetworks called biofilms, and formation of biofilms results in increased resistancetowards antifungal compounds currently in use. Therefore, there is a need foralternative antifungal compounds such as fatty acids. Research has shown thatsupplementation of growth medium with polyunsaturated fatty acids (PUFAs), increasedthe unsaturation index and made cells susceptible to lipid peroxidation and cell death.During this study this phenomenon was evaluated on biofilms of C. albicans and C.dubliniensis using selected PUFAs. Due to differences in the carbon chain length andsaturation of fatty acids, they interact differently with the cell membrane and will havedifferent peroxidisability values. The results from the study showed C18:4 n-3 andC20:5 n-3 were taken in by the cell and resulted in increased unsaturation index. Theresults further indicated oxidative stress-induced apoptosis following supplementationwith C18:4 n-3 and C20:5 n-3 in biofilms of both C. albicans and C. dubliniensis. Theinduction of apoptosis following supplementation by C18:4 n-3 and C20:5 n-3 wasconfirmed by mitochondrial membrane potential assay, Annexin V-FITC staining,TUNEL assay and DAPI staining. The use of C18:4 n-3 in synergism with amphotericinB resulted in decreased dosage of the antifungal compound needed to inhibit biofilms ofC. albicans and C. dubliniensis.

[发布机构] University of the Free State