Associação da Quitosana e Clorexidina contra formação de biofilmes por Estreptococos do grupo Mutans e Candida sp. em escovas dentais

Abstract

The oral cavity is colonized by several commensal microorganisms and by others with pathogenic potential. In this anatomical site, mutans group streptococci (MGS) and Candida (Ca) are highlighted as etiological agents that participate in the development of dental caries and candidiasis, respectively. The formation of microbial biofilm is an important virulence factor that contributes to the pathogenicity of these microorganisms. The objective of this research is to evaluate the effect of chitosan, chlorhexidine and the combination of the two on the formation of MGS and Ca biofilm on toothbrushes. For this purpose, saliva samples were collected from 12 students from the Universidade Estadual de Goiás for the isolation and presumptive identification of microorganisms based on growth in selective media and analysis of the macroscopic morphology of the colonies. MGS were isolated in 10 samples with a predominance of colonies with a mucoid aspect and in 5 samples colonies with a suggestive Ca aspect were isolated. Subsequently, the microorganisms were cultured on toothbrushes soaked in culture broth to evaluate the biofilm formation of the isolates. The results indicated that all microbial isolates were able to form biofilms under the conditions tested, with microbial cell counts adhered to the biofilm ranging from 6.75 to 11.00 Log10 cfu.ml-1 for mutans streptococci and 4.94 to 5.79 Log10 cfu.ml-1 for Candida sp. Subsequently, the impact of 1 mg.mL-1 chitosan solution, 0.60 mg.mL-1 chlorhexidine solution and the association of both on the biofilm formation of the isolates on pre-treated toothbrushes was evaluated. The results indicated that chitosan reduced the biofilm formation of the MGS4 and MGS5 isolates on the pre-treated brushes. Chlorhexidine was able to reduce biofilm formation by all MGS and Ca8. The combination of compounds was effective against MGS4, MGS5 and Ca2. In summary, in this work we evaluated the formation of biofilm on toothbrushes by mutans streptococci and Candida sp. isolated from the mouths of students at the State University of Goiás. The sample collection methodology proved to be effective, as the microorganisms were not recovered in just one brush collected. In the second part of the study, it was found that all isolates were able to form biofilms on toothbrushes, which reinforces the importance of taking care with decontamination of toothbrushes in promoting oral health. Therefore, it can be concluded that chlorhexidine was the compound with the highest biofilm-reducing activity of MGS and Ca, followed by the association of chitosan and chlorhexidine; only chitosan had the lowest inhibition results only on MGS and without Ca action. The combination of compounds was not able to intensify the biofilm reduction of chlorhexidine alone, but the association was more effective than chitosan.