Anais do Congresso Paranaense de Microbiologia
Anais do IV Congresso Paranaense de Microbiologia

Candida albicans is commonly related to infections in different anatomical sites. The use of antifungals in recent decades, and the prolonged exposure to them, has caused the spread of resistant strains, leading to the research of new extremely relevant antifungal substances. Thus, the present study aimed to analyze the antifungal activity of the F4a fraction obtained from the culture of Pseudomonas aeruginosa LV in reference strains of C. albicans (ATCC 10231 and ATCC 26790) and clinical isolates (n = 16) obtained from different anatomical sites. The effect of the fraction on the expression of the C. albicans HWP1, EFG1 and BCR1 genes and the viability of mammalian cells were also analyzed. Antimicrobial activity of fluopsin C, one of the compounds of F4a fraction, was tested on C. albicans ATCC 10231. The F4a fraction exhibited fungistatic (MIC: 1.56-6.25µg/mL) and fungicidal activity (MFC: 6.25 to 25µg/mL) for planktonic cells, and sessile cells (SMIC₉₀: 12.5µg/mL-25µg/mL), regardless of clonal profiles and resistance profiles to fluconazole and voriconazol. The MIC for fluopsin C was 1.56 µg/mL; MFC was 25µg/mL and SMIC₉₀ was 6.25µg/mL. The inhibitory effect of both F4a and fluopsin C was observed after 16 h, when compared to the untreated control. Morphological changes such as cytoplasmic vacuolization, membrane retraction and cytoplasmic disorganization were observed in planktonic cells exposed to F4a (1.56-25µg/ mL). The expression levels of the HWP1, BCR1 and EFG1 C. albicans genes were decreased when treated with F4a, whereas Fluopsin C decreased only the expression of HWP1. The F4a fraction (50µg/mL) and fluopsin C (50µg/mL) produced approximately 4% and 2% of hemolysis in human erythrocytes, and the cytotoxic concentration for 50% of HeLa cells was 0.86 µg/mL and 0.43 µg/mL, respectively. When compared the antifungal activity of the F4a fraction and fluopsin C, it can be seen that they were similar in relation to MIC, growth kinetics, and in reducing the metabolic activity of biofilm. The results indicate that the antifungal activity of the F4a fraction is related to fluopsin C. However, F4a has less toxicity to mammalian cells and is less costly to obtain. Altogether, these results reinforce the use of the F4a fraction in studies for the development of new strategies for the treatment of candidiasis