Effects of Lactobacillus spp. isolated from oral cavity of caries-free subjects on Streptococcus mutans: study of potencial probiotic

Author(s)

Marisol dos Santos Velloso

• Document type: Master's Dissertation
• Press: São José dos Campos. 2016-10-27.
• Institution: Universidade Estadual Paulista (Unesp). Instituto de Ciência e Tecnologia. São José dos Campos
• Defense date: 2016-09-22
• Advisor: Juliana Campos Junqueira

Abstract

Previous studies have demonstrated that certain strains of Lactobacillus can inhibit Streptococcus mutans. Thereby, Lactobacillus strains belonging to the oral microbiota resident from healthy subjects need to be investigated as possible strategies to prevent dental caries and other oral infections. The aim of this study was to evaluate the effect of Lactobacillus spp. strains isolated from caries-free subjects on S. mutans using study models in vitro and in vivo. In the in vitro study, thirty Lactobacillus strains recovered from the oral cavity of caries-free subjects were evaluated for antibacterial activity against S. mutans in planktonic culture. Next, the five strains that showed higher antibacterial activity were selected for the study of antimicrobial effects on biofilm of S. mutans formed on hydroxyapatite disks. For in vivo study, we selected the Lactobacillus strain with greater inhibitory effect on S. mutans biofilm, in order to evaluate its effects on the development of experimental caries in rats. The results showed that most of the tested Lactobacillus strains were able to inhibit S. mutans cells in planktonic culture, reaching a percentage reduction up to 99 %. The strains with higher percentage of inhibition selected for biofilm tests were one strain of L. fermentum and four of L. paracasei. All five of these strains were able to inhibit biofilm formation of S. mutans, however statistically significant differences were only observed for three strains. Thus, for the dental caries test in rats was used only one strain of L. paracasei. Treatment with this Lactobacillus strain has led to a reduction in the number of CFU / mL of S. mutans in the oral cavity of the animals but had no effect on the development of dental caries. In all experimental groups enamel demineralization areas were observed, but cavitary lesions were not detected. It was concluded that L. fermentum and L. paracasei strains tested have a potential probiotics and could be used in the oral cavity because they have inhibitory activity against S. mutans and reduce biofilm formation by this cariogenic micro-organism. (AU)

• FAPESP's process: 14/11841-9 - Effects of Lactobacillus spp. isolated from oral cavity of caries-free subjects on Streptococcus mutans: study of probiotic activity
• Grantee: Marisol dos Santos Velloso
• Support Opportunities: Scholarships in Brazil - Master