Efeito do sobrenadante de Streptococcus mutans e Candida albicans em biofilmes mono e duo-espécie

Abstract

Streptococcus mutans (S. mutans) is one of the most common bacteria in cariogenic biofilms. Considering the polymicrobial nature of dental caries, symbiotic relationships between different kingdoms should be studied. Thus, the aim of the present study was to evaluate the action of the supernatant of Streptococcus mutans and/or Candida albicans on the formation, composition and morphology of mono (M) and dual-specie (D) biofilms of these microorganisms.The test of microbial adhesion to the hydrocarbon was carried out to evaluate cell hydrophobicity. For the microbiological assay, the biofilms were grown in vitro in the presence of the studied supernatant combined or isolated, cultured in RPMI medium for 48 hours (5% CO2 at 37 °C). After established growth period, the biofilms were collected and seeded for CFU(Colony Forming Unit) analysis and quantification of extracellular polysaccharides (EPS-insoluble and soluble) to determine the total polysaccharides (PECT). Scanning Electron Microscopy (SEM) and Laser Confocal Microscopy (LCM) examined the biofilm morphology. Data was analyzed using ANOVA, followed by the bonferroni test, with a significance level set at 5%. The relative hydrophobicity (RH) of S. mutans cells increased by 6.8 fold in the presence of the C. albicans supernatant, whereas the HR of C. albicans increased 1.2 fold in the presence of its own supernatant. Regarding M biofilms of S. mutansdid not show statistical difference in the presence of supernatants, however, in relation to C. albicans was an increase counts was observed when cultured with S. mutans supernatant (p=0.0487). For D biofilms, the presence of C. albicans supernatant significantly reduced S. mutans counts (p=0.0454). S. mutans supernatant there was a significant (p <0.05) increase in PECT production in both M and D biofilms. The SEM data suggest an increase in C. albicans filamentation when in contact with the supernatants tested. In relation to the LCM, an increase of the biofilm biomass of S. mutans was observed when in contact with the two supernatants. It is concluded that the supernatant of S. mutans alone influences in the increase of C. albicans and in the increase of the PECT production of both microorganisms studied indicating interactions between these microorganisms in the biofilm.