Análise do perfil morfológico de candida tropicalis durante a formação do biofilme sob influência de metabólitos extracelulares de bactérias do gênero streptococcus

Abstract

Bacteria and fungi are found together in a multitude of environments, and particularly in the form of biofilm adherent species which interact through various signaling mechanisms. In the oral cavity, Candida species coexist with numerous bacterial species, and evidence suggests that bacteria can modulate biofilm formation as well as induce the formation of hyphae. Thus, to characterize such interactions are essential to the understanding of pathogenesis of diseases and possibly the discovery of new therapeutic strategies. In this sense, the main objective of this study was to evaluate, in vitro, the mechanisms involved in the interaction between bacteria Streptococcus oralis, Streptococcus sanguinis, and Streptococcus parasanguinis yeast Candida tropicalis. In the study the effect of extracellular metabolites present in the supernatant of C. tropicalis (SCT) on the pre-formed biofilm (6H) S. oralis, S. sanguinis and S. parasanguinis was analyzed. The effect of extracellular metabolites of S. oralis (SSO), S. sanguinis (SSS) and S. parasanguinis (SSP) on planktonic growth and biofilm formation capacity filamentation of C. tropicalis was also evaluated using only the supernatant culturing each of streptococci in different concentrations (100, 50 and 25%). Furthermore, the effect of extracellular metabolites of streptococci on the pre-formed biofilm (6h) of C. tropicalis were analyzed. To verify the effect of extracellular metabolites two methods were used: The turbidimetric method based on the reading of the optical density (OD) of cell suspension and coloring crystal violet (CV) which permits indirect quantification of the biofilm formation by staining with crystal violet. Then were examined characteristics of biofilms formed by 24 hours, through the analysis simple optical microscope. The results for the biofilm were subjected to ANOVA with Bonferroni post-test, with a statistical difference of p<0.01.Our results suggest that soluble substances produced by S. oralis, S. sanguinis and S. parasanguinis induce the formation of hyphae of C. tropicalis without interfering with planktonic growth.In addition to dramatically decrease biofilm development of oral yeast when in contact with SSP and SSS. This reinforces the idea that there is great heterogeneity within polymicrobial biofilms, especially between yeasts and bacteria. And the result of this interaction depends on the conditions which these micro-organisms will be subjected.