Characterization of Biofilm Formation and Structure and Their Inhibition by Pea Defensin d2.

Approximately four million people contract fungal infections every year in Brazil, primarily caused by . The ability of these fungi to form biofilms in tissues and medical devices complicates treatment and contributes to high rates of morbidity and mortality in immunocompromised patients. d2 is a pea defensin of 5.4 kDa that possesses good antifungal activity against planktonic cells of representative pathogenic fungi. Its function depends on interactions with membrane and cell wall lipid components such as glucosylceramide and ergosterol. In the present study, we characterized biofilm formation and determined the effect of d2 on biofilms. After 4 hours, conidia adhered to polystyrene surfaces and formed a robust extracellular matrix-producing biofilm at 24 h, increasing thickness until 48 h d2 inhibited biofilm formation in a dose-dependent manner. Most notably, at 10 μM d2 inhibited 50% of biofilm viability and biomass and 40% of extracellular matrix production. d2 significantly decreased the colonized surface area by the biofilm and changed its level of organization, causing a shortening of length and diameter of hyphae and inhibition of conidiophore formation. This activity against biofilm suggests a potential use of d2 as a prototype to design new antifungal agents to prevent biofilm formation by and related species.