RESUMO
Probiotics have decreased the counts of salivary mutans streptococci (MS) in clinical studies. The aim of this study was to compare the effects of Lactobacillus reuteri PTA 5289 and L. paracasei DSMZ16671 on the adhesion of a reference strain and a clinical isolate of Streptococcus mutans and on the counts of MS in a biofilm. The adhesion of S. mutans Ingbritt and the clinical isolate S. mutans 2366 to a smooth glass surface and saliva-coated hydroxyapatite (SHA) were studied in the presence of and without the lactobacilli. A three-species biofilm formed on saliva-coated hydroxyapatite discs was used in the biofilm experiments. The lactobacilli did not affect adhesion to the glass surface but interfered with binding to SHA. No effects of the lactobacilli were detected on the MS levels in the three-species biofilms. The results of the SHA binding experiments best reflected the results of the existing clinical studies.
Assuntos
Aderência Bacteriana/efeitos dos fármacos , Biofilmes/efeitos dos fármacos , Lactobacillus/fisiologia , Limosilactobacillus reuteri/fisiologia , Probióticos/farmacologia , Streptococcus mutans/fisiologia , Humanos , Infecções Estreptocócicas/microbiologia , Streptococcus mutans/efeitos dos fármacosRESUMO
We studied the effects of xylitol on biofilms containing xylitol-resistant (Xr) and xylitol-sensitive (Xs) Streptococcus mutans, Actinomyces naeslundii and S. sanguinis. The biofilms were grown for 8 and 24 h on hydroxyapatite discs. The viable microorganisms were determined by plate culturing techniques and fluorescence in situ hybridization (FISH) was performed using a S. mutans-specific probe. Extracellular cell-bound polysaccharides (EPS) were determined by spectrofluorometry from single-species S. mutans biofilms. In the presence of 5 % xylitol, the counts of the Xs S. mutans decreased tenfold in the young (8 h) biofilm (p < 0.05) but no effect was seen in the mature (24 h) biofilm. No decrease was observed for the Xr strains, and FISH confirmed these results. No differences were detected in the EPS production of the Xs S. mutans grown with or without xylitol, nor between Xr and Xs S. mutans strains. Thus, it seems that xylitol did not affect the EPS synthesis of the S. mutans strains. Since the Xr S. mutans strains, not inhibited by xylitol, showed no xylitol-induced decrease in the biofilms, we conclude that growth inhibition could be responsible for the decrease of the counts of the Xs S. mutans strains in the clinically relevant young biofilms.
Assuntos
Antibacterianos/farmacologia , Biofilmes/efeitos dos fármacos , Streptococcus mutans/efeitos dos fármacos , Xilitol/farmacologia , Análise de Variância , Biofilmes/crescimento & desenvolvimento , Contagem de Colônia Microbiana , Humanos , Hibridização in Situ Fluorescente , Saliva/microbiologia , Streptococcus mutans/fisiologiaRESUMO
Acidogenicity and the levels of mutans streptococci (MS) in dental plaque after the use of Lactobacillus rhamnosus GG (LGG) and Lactobacillus reuteri were determined. The study had a randomised, double-blind, crossover design. Thirteen volunteers used tablets containing LGG or a combination of L. reuteri SD2112 and PTA 5289 for 2 weeks. At baseline and at the end of each tablet period, all available supragingival plaque was collected. Lactic acid production was determined from a fixed volume (8 µl) of fresh plaque and the rest of the plaque was used for culturing MS and lactobacilli. The retention of probiotics to the plaque was assessed using PCR techniques. No probiotic-induced changes were found in the acidogenicity of plaque. Also, MS counts remained at the original level. The number of subjects with lactobacilli in plaque increased in the L. reuteri group (p = 0.011) but not in the LGG group. PCR analysis of plaque revealed the presence of LGG in four and L. reuteri in six subjects after the use of the probiotic. The use of the lactobacilli did not affect the acidogenicity or MS levels of plaque. Short-term consumption of LGG and L. reuteri appeared not to influence the acidogenicity of plaque.
Assuntos
Placa Dentária/metabolismo , Placa Dentária/microbiologia , Probióticos/farmacologia , Streptococcus mutans/efeitos dos fármacos , Streptococcus mutans/metabolismo , Adulto , Aderência Bacteriana , Contagem de Colônia Microbiana , Estudos Cross-Over , Método Duplo-Cego , Feminino , Humanos , Ácido Láctico/análise , Ácido Láctico/metabolismo , Limosilactobacillus reuteri , Lacticaseibacillus rhamnosus , Masculino , Probióticos/administração & dosagem , Especificidade da Espécie , Estatísticas não Paramétricas , Comprimidos , Fatores de TempoRESUMO
In clinical studies, probiotic bacteria have decreased the counts of salivary mutans streptococci (MS). We compared the effects of probiotic Lactobacillus strains on the biofilm formation of Streptococcus mutans. The bacterial strains used included four S. mutans strains (reference strains NCTC 10449 and Ingbritt and clinical isolates 2366 and 195) and probiotic strains Lactobacillus rhamnosus GG, L. plantarum 299v, and L. reuteri strains PTA 5289 and SD2112. The ability of MS to adhere and grow on a glass surface, reflecting biofilm formation, was studied in the presence of the lactobacilli (LB). The effect of LB culture supernatants on the viability of the MS was studied as well. All of the LB inhibited the biofilm formation of the clinical isolates of MS (P < 0.001). The biofilm formation of the reference strains of MS was also inhibited by the LB, but L. plantarum and L. reuteri PTA 5289 showed a weaker inhibition when compared to L. reuteri SD2112 and L. rhamnosus GG. Viable S. mutans cells could be detected in the biofilms and culture media only when the experiments were performed with the L. reuteri strains. The L. reuteri strains were less efficient in killing the MS also in the tests performed with the culture supernatants. The pHs of the supernatants of L. reuteri were higher compared to those of L. rhamnosus GG and L. plantarum; P < 0.001. In conclusion, our results demonstrated that four commonly used probiotics interfered with S. mutans biofilm formation in vitro, and that the antimicrobial activity against S. mutans was pH-dependent.