Secreted Products Inhibit Induced Oral Candidiasis.

In the oral cavity, species form mixed biofilms with , a pathogenic bacterium that can secrete molecules with antifungal activity. In this study, we extracted and fractioned culture filtrate of , seeking antifungal agents capable of inhibiting the biofilms, filamentation, and candidiasis by . Active UA159 supernatant filtrate components were extracted via liquid-liquid partition and fractionated on a C-18 silica column to resolve fraction 1 (SM-F1) and fraction 2 (SM-F2). We found anti-biofilm activity for both SM-F1 and SM-F2 in a dose dependent manner and fungal growth was reduced by 2.59 and 5.98 log for SM-F1 and SM-F2, respectively. The SM-F1 and SM-F2 fractions were also capable of reducing filamentation, however statistically significant differences were only observed for the SM-F2 ( = 0.004). SM-F2 efficacy to inhibit was confirmed by its capacity to downregulate filamentation genes , , , and . Using as an invertebrate infection model, therapeutic treatment with SM-F2 prolonged larvae survival. Examination of the antifungal capacity was extended to a murine model of oral candidiasis that exhibited a reduction in colonization (CFU/mL) in the oral cavity when treated with SM-F1 (2.46 log) and SM-F2 (2.34 log) compared to the control (3.25 log). Although both SM-F1 and SM-F2 fractions decreased candidiasis in mice, only SM-F2 exhibited significant quantitative differences compared to the non-treated group for macroscopic lesions, hyphae invasion, tissue lesions, and inflammatory infiltrate. Taken together, these results indicate that the SM-F2 fraction contains antifungal components, providing a promising resource in the discovery of new inhibitors for oral candidiasis.