P002 Antifungal activity of antimicrobial synthetic peptides against Candida species of public health importance

POSTER SESSION 1, SEPTEMBER 21, 2022, 12:30 PM - 1:30 PM: BACKGROUND: Candidiasis is one of the most frequent opportunistic infections in immunosuppressed and/or hospitalized patients. In countries like Colombia, candidiasis is associated with a mortality rate of ∼ 46%. Growing pharmacological resistance of Candida spp., and the appearance of the emerging pathogen Candida auris, have turned candidiasis into a major public health problem. Different types of antimicrobial peptides have been investigated as a therapeutic alternative to control candidiasis effectively and safely. OBJECTIVE: This work aimed at evaluating the in vitro antifungal activity of three synthetic antimicrobial peptides (35 409, 1609, and 29 009) obtained from Plasmodium falciparum Rif1 protein against C. auris, C. albicans, C. glabrata, C. parapsilosis, C. krusei, and C. tropicalis, species with worldwide clinical importance. METHODS: The minimum inhibitory concentrations (MIC) of the three peptides against Candida species were determined by the plate microdilution method; the peptides’ effect on biofilm formation in C. auris and C. albicans species was also evaluated through the XTT metabolic activity assay. Additionally, the structural damages in C. auris and C. albicans caused by the action of the peptides were observed by transmission electron microscopy (TEM) and finally, the in vitro peptides’ cytotoxicity against L929 murine fibroblasts was verified. RESULTS: Our findings showed that the three peptides herein evaluated, displayed antifungal activity in both planktonic and sessile Candida cells. Likewise, the TEM evidenced morphological alterations induced by the peptides, both in the membrane and at the intracellular level of the yeasts. As well, total safety against the murine cell line L929 with 24 h of treatment was observed. CONCLUSIONS: From these results, we conclude that the antimicrobial peptides 35 409, 1609, and 29 009 are potential therapeutic alternatives against the most important Candida species in Colombia and the world.