IADR Abstract Archives
Effects of Epigallocatechin-3-Gallate on Properties of a Double-Species Cariogenic Biofilm
Objectives: Epigallocatechin-3-gallate (EGCG) was shown to be a potential caries-protective agent and an inhibitor against biofilm formation of the cariogenic Streptococcus mutans (Sm). However, whether EGCG could still reduce biofilm formation when an antigonizer of Sm, S. sanguinis (Ss), was present. In this study, effects of EGCG on the properties of biofilms formed by Sm or/and Ss were characterized.
Methods: Biofilms of Sm alone, Ss alone or Sm-Ss co-cultures (Sm-Ss) were formed in the absence or presence of EGCG (0-16μg/ml) in chemically defined media. Biomass of biofilms were measured by the crystal violet assay. Morphology were observed by scanning electron microscopy (SEM). Distribution of live/dead bacteria, extracellular polysaccharides (EPS) or extracellular DNA (eDNA) was stained with the LIVE/DEAD kit, Fluorescein-conjugated dextran or SYTOX, respectively, and then observed by confocal laser microscopy. Concentrations of H2O2 in culture media were determined by the Amplex Red assay.
Results: EGCG (4μg/ml) reduced biomass or levels of live bacteria in Sm biofilms, when 2μg/ml was required reduction in SS or Sm-Ss biofilm. Bacterial density in biofilms was also decreased by EGCG. Growing biofilms with 0-2μg/ml EGCG did not change levels of dead bacteria in Sm biofilms, which, meanwhile, were higher than Ss or Sm-Ss biofilms. EGCG (4μg/ml) reduced amounts of dead bacteria in Sm biofilms, while 8μg/ml decreased dead bacteria in Ss or Sm-Ss biofilms. EPS responded to EGCG similarly to changes in dead bacteria; however, the level of EPS tended to be higher in Sm-Ss biofilms than in Sm biofilms. EGCG (0-8μg/ml) gradually increased eDNA in Sm or Sm-Ss biofilms in a dose-dependent manner, but it didn’t affect eDNA levels in Ss biofilms. EGCG decreased H2O2 levels of Ss or Sm-Ss groups in a dose-dependent manner, while H2O2 was unaffected in Sm groups.
Conclusions: EGCG differently interfered properties of Sm, Ss or Sm-Ss biofilms.
Methods: Biofilms of Sm alone, Ss alone or Sm-Ss co-cultures (Sm-Ss) were formed in the absence or presence of EGCG (0-16μg/ml) in chemically defined media. Biomass of biofilms were measured by the crystal violet assay. Morphology were observed by scanning electron microscopy (SEM). Distribution of live/dead bacteria, extracellular polysaccharides (EPS) or extracellular DNA (eDNA) was stained with the LIVE/DEAD kit, Fluorescein-conjugated dextran or SYTOX, respectively, and then observed by confocal laser microscopy. Concentrations of H2O2 in culture media were determined by the Amplex Red assay.
Results: EGCG (4μg/ml) reduced biomass or levels of live bacteria in Sm biofilms, when 2μg/ml was required reduction in SS or Sm-Ss biofilm. Bacterial density in biofilms was also decreased by EGCG. Growing biofilms with 0-2μg/ml EGCG did not change levels of dead bacteria in Sm biofilms, which, meanwhile, were higher than Ss or Sm-Ss biofilms. EGCG (4μg/ml) reduced amounts of dead bacteria in Sm biofilms, while 8μg/ml decreased dead bacteria in Ss or Sm-Ss biofilms. EPS responded to EGCG similarly to changes in dead bacteria; however, the level of EPS tended to be higher in Sm-Ss biofilms than in Sm biofilms. EGCG (0-8μg/ml) gradually increased eDNA in Sm or Sm-Ss biofilms in a dose-dependent manner, but it didn’t affect eDNA levels in Ss biofilms. EGCG decreased H2O2 levels of Ss or Sm-Ss groups in a dose-dependent manner, while H2O2 was unaffected in Sm groups.
Conclusions: EGCG differently interfered properties of Sm, Ss or Sm-Ss biofilms.