Resumo

Candidemia are a major cause of morbidity and mortality in hospitals. Candida species represent a group of medically important pathogenic fungi. Antimicrobial resistance has become increasingly important in antifungal therapy due to resistance to almost all antifungal agents, especially fluconazole (FLC), has been found in clinical isolates of Candida spp. Thus, the search for new therapeutic strategies has become a pressing concern. Chitin-binding proteins are a class of bioactive proteins wichi possess several biological activities. Recently, these proteiens were the focus of diferente pharmacological studies. The goal of the current study was to evaluate the antifungal activity of a chitin-binding vicilin from the seeds of Erythrina velutina against isolates of FLC-resistant C. albicans using the microdilution antifungal susceptibility test according to CLSI protocol M27-S4. Also, the cytotoxic effect of drugs against human skin fibroblast and lymphocytes was assessed by Alamar Blue assay after 72 h exposure (37°C). Candida cultures were single exposed to FLC or vicilin at a range of concentrations from 0.125-64 µg/mL or co-treated with FLC and vicilin for 48 h (35°C), and the results were examined visually, as recommended by the CLSI. Single exposure to vicilin or FLC showed no activity against FLC-resistant strains of C. albicans (MIC > 64 µg/mL) or human cells (IC50 > 64 µg/mL). In contrast, when these strains were co-treated (vicilin plus FLC) a synergistic effect of the drugs on FLC-resistant strains of C. albicans growth was observed, as demonstrated by reduction of MIC values (0.125 µg/mL) and by fractional inhibitory concentration index (FICI ≤ 0.5), but showed non-toxicity in human cells. In summary, combination of vicilin with FLC demonstrated antifungal activity against strains of fluconazole-resistant C. albicans in vitro.