Managing dental caries via manipulating war and peace within oral-microbial-communities

Objectives: Bacteria in nature exist almost exclusively in multispecies communities known as the biofilm. In a natural habitat, the entire community must act as a whole to cope with various adverse conditions and maximize their utilization of available resources. On the other hand, however, each individual species wihtin a community must compete with other species occupying the same niche for the limited nutrients and space. How competition among different species results in coexistence in the same niche is an intriguing question, and answers to this question may provide insight into the molecular basis of biodiversity in natural microbial communities. We use oral biofilms (dental plaque) as a model system to address this problem. Methods and Results: Using genetic, biochemical and genomic approaches, our laboratory discovered that sophisticatedly regulated bacteriocin production and inter-species signaling plays an essential role in balancing competition and coexistence between different oral bacteria. Most interestingly, we will report a coordinated regulation between bacteriocin production and competence development, which may serve as a means for S. mutans to forcefully acquire DNA from neighboring species under stress. We have further used the knowledge learned from inter-species interactions to develop diagnostic and therapeutic tools against oral microbial pathogenesis. Conclusion: Modulating the inter-species interactions within oral microbial communities provide a unique way to control oral microbial pathogenesis. The study was supported by grants from NIH and University of California.