A Holistic View of Inter-species Bacterial Interactions within Human Dental Plaque
Alexander H. Rickard, Adam J. Underwood and William Nance
from: Oral Microbial Ecology: Current Research and New Perspectives (Edited by: Nicholas S. Jakubovics and Robert J. Palmer Jr.). Caister Academic Press, U.K. (2013)
Mature dental-plaque biofilm communities contain hundreds of bacterial species. The potential for these communities to cause caries or periodontal disease relates to bacterial spatiotemporal biofilm development and species composition. At least three forms of inter-species interactions can conceivably mediate altered biofilm development and species composition. These are coaggregation, metabolic interactions, and cell-cell signaling. Coaggregation is the specific recognition and adhesion of different species of bacteria and likely contributes toward the ordered (sequential) integration of species into biofilms as well as improving species retention in a flowing environment. 'Metabolic interactions' is an umbrella term that describes the exchange of metabolites or environmental protection afforded between adjacent species within dental plaque. Cell-cell signaling is a phenomenon that has gained increasing research interest over the past decade. One broad inter-species signaling molecule system consists of a collection of inter-convertible cell-cell signal molecules that are collectively called autoinducer-2 (AI-2). Evidence indicates that AI-2 can alter bacterial phenotypes, when present in saliva at concentrations as low as the nanomolar range. It is the aim of this chapter to describe each of these inter-species phenomena, with case-examples, and extrapolate singular and combined roles in the spatio-temporal development of dental plaque. The potential for these phenomena to create shifts in community species composition have implications for the development of polymicrobial diseases read more ...