Atividade anti-biofilme de Proteinase K e DNAse I e de antimaláricos sobre biofilmes duo-espécie de Candida albicans e Streptococcus mutans

Abstract

Candida albicans is a commensal fungus capable of interacting with bacteria such as Streptococcus mutans commonly associated with dental caries due to its ability to metabolize sucrose and favor coadhesion with other microorganisms. These microorganisms can also cause other oral pathologies associated with neglected diseases, such as malaria. The aim of this study was to evaluate the anti-biofilm effect of proteinase K and DNAse I and the antimalarials chloroquine and primaquine on duo-species biofilms of C. albicans and S. mutans. The values of the lowest concentration capable of inhibiting 50% of the biofilm compared to the control were determined by microdilution tests in broth with 8 strains of C. albicans, including the strain of C. albicans ATCC 10231 in combination with 1 strain of S. mutans ATCC 25175. After treatment with concentrations of 4 to 128µg/mL for proteinase K and DNAse I and 32 to 1,024µg/mL for chloroquine and primaquine, the biofilms were evaluated for biomass using crystal violet staining and metabolic activity by MTT [3-(4,5- dimethylthiazol-2yl)-2,5-diphenyl tetrazolium] reduction assay. Subsequently, microscopic images were performed using confocal microscopy (proteinase K and DNAse I) and scanning electron microscopy (proteinase K, DNAse I, chloroquine and primaquine). Proteinase K reduced (P<0.001) the biomass and metabolic activity of biofilms reaching maximum inhibitions of 58.66% and 71.33% at concentrations from 16 µg/mL and 4 µg/mL, respectively. DNAse I reduced (P <0.001) the biomass and metabolic activity of biofilms, reaching the maximum inhibition of 49.63% and 55.62%, at concentrations from 32 µg/mL and 4 µg/mL, respectively. Chloroquine reduced (P<0.001) the metabolic activity of biofilms by 49.8% at the lowest tested concentration of 32µg/mL and 74.9% at the highest tested concentration of 1024 µg/ml. Primaquine at its lowest tested concentration of 32 µg/mL, inhibited 35.91% of the metabolic activity and at the highest concentration of 1,024 µg/mL there was an inhibition of 74.2%. Tests were also performed associating chloroquine and primaquine 32 µg/mL of each drug. The combination of drugs inhibited 33.84% of the metabolic activity when compared to the control. The images demonstrated the anti-biofilm (proteinase k and DNAse I) and antimicrobial (primaquine and chloroquine) effect of the drugs under study