Periodontal pathogens interfere with quorum-sensing-dependent virulence properties in Streptococcus mutans.
OBJECTIVE
The mechanism by which periodontal pathogens dominate at disease sites is not yet understood. One possibility is that these late colonizers antagonize the quorum-sensing systems of early colonizers and render those early colonizers less resistant to environmental factors. In this study, we utilized Streptococcus mutans, a well-documented oral Streptococcus with many quorum-sensing-dependent properties, as an example of an earlier colonizer antagonized by periodontal pathogens.


METHODS
In this study, S. mutans NG8 and S. mutans LT11 were used in experiments assessing transformation, and S. mutans BM71 was used in experiments investigating bacteriocin production. The effects of the periodontal pathogens Porphyromonas gingivalis and Treponema denticola on these competence-stimulating peptide-dependent properties were evaluated in mixed-broth assays.


RESULTS
Both P. gingivalis (either live bacteria or membrane vesicles) and T. denticola antagonized transformation in S. mutans NG8 and LT11. The production of bacteriocin by S. mutans BM71 was also inhibited by P. gingivalis and T. denticola. Boiling of these late colonizers before addition to the broth cultures abolished their ability to inhibit S. mutans transformation and bacteriocin production. P. gingivalis and T. denticola inactivated S. mutans exogenous competence-stimulating peptide, whereas the boiled bacteria did not.


CONCLUSIONS
This study demonstrated that periodontal pathogens antagonize S. mutans quorum-sensing properties. This may render S. mutans less virulent and less resistant to environmental antibacterial factors.
Department of Periodontics and Endodontics, University at Buffalo, State University of New York, Buffalo, NY 14214, USA. bwang@buffalo.edu
B Y
BY
Wang
P
P
Alvarez
J
J
Hong
H K
HK
Kuramitsu
D000898:Antibiosis / Q000235:genetics; D001426:Bacterial Proteins / Q000037:antagonists & inhibitors* / Q000235:genetics; D001430:Bacteriocins / Q000037:antagonists & inhibitors / Q000096:biosynthesis; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D016966:Porphyromonas gingivalis / Q000502:physiology*; D053038:Quorum Sensing / Q000502:physiology*; D015398:Signal Transduction / Q000235:genetics; D013295:Streptococcus mutans / Q000235:genetics / Q000502:physiology*; D014169:Transformation, Bacterial; D048373:Treponema denticola / Q000502:physiology*; D014774:Virulence / Q000235:genetics
D001426:Bacterial Proteins; D001430:Bacteriocins; C423628:competence factor, Streptococcus