Inhibitory effects of tea catechin epigallocatechin-3-gallate against biofilms formed from Streptococcus mutans and a probiotic lactobacillus strain.
OBJECTIVE
Effects of tea catechin epigallocatechin-3-gallate (EGCG) against biofilm formation by Streptococcus mutans and probiotic Lactobacillus casei in Yakult® (LcY) were examined.


DESIGN
Biofilms were formed by S. mutans alone (Sm) and co-culture of S. mutans and LcY (Sm + LcY) in the absence or presence of EGCG. The biomass of biofilms, which were sonicated or not, was measured by the crystal violet assay. Biofilm morphology was observed by scanning electron microscopy. Bacterial viability and extracellular polysaccharides were determined by SYTO9/propidium iodide and dextran-conjugated fluorescein staining, respectively, and confocal microscopy. Gene expression of glucosyltransferase was determined by quantitative polymerase chain reaction.


RESULTS
While 250 μg/ml EGCG significantly decreased the biomass and acid production of Sm biofilms, 500 μg/ml EGCG was required to inhibit Sm + LcY biofilm formation and acid production. EGCG decreased the amount of live bacteria present in both Sm and Sm + LcY biofilms. The level of dead bacteria in Sm + LcY biofilms was higher than in Sm biofilms when formed in the presence of 250 μg/ml EGCG. EGCG decreased levels of extracellular polysaccharides in Sm and Sm + LcY biofilms. The extent of biofilm removal by sonication was not different between Sm and Sm+LcY biofilms formed in the absence or presence of 62.5 or 125 μg/ml EGCG. The level of Sm gtfB and gtfD expression in Sm + LcY biofilms was higher than those in the Sm biofilms when formed in the presence of EGCG at 250 μg/ml.


CONCLUSION
The results indicated that LcY might interfere the inhibitory effects of EGCG against biofilm formation by S. mutans.
['Wu|Ching-Yi|CY|', 'Su|Tzu-Yi|TY|', 'Wang|Mao-Yu|MY|', 'Yang|Shue-Fen|SF|', 'Mar|Kwei|K|', 'Hung|Shan-Ling|SL|']
D000900:Anti-Bacterial Agents D001426:Bacterial Proteins D018441:Biofilms D018533:Biomass D002392:Catechin D004305:Dose-Response Relationship, Drug D015964:Gene Expression Regulation, Bacterial D005964:Glucosyltransferases D007780:Lactobacillus casei D008826:Microbial Sensitivity Tests D050296:Microbial Viability D011134:Polysaccharides D019936:Probiotics D013295:Streptococcus mutans D013662:Tea
Epigallocatechin-3-gallate Biofilms Streptococcus mutans Probiotic Lactobacillus casei