Periodontal pathogens produce quorum sensing signal molecules.

Different species of bacteria important in the composition of dental plaque were tested for production of extracellular autoinducer-like activities that stimulate the expression of the luminescence genes in Vibrio harveyi. Several strains of Prevotella intermedia, Fusobacterium nucleatum, and Porphyromonas gingivalis were found to produce such activities. Interestingly, these bacteria belong to the same phylogenetic group, and they are periodontal pathogens important in the development of periodontal disease. They specifically produce extracellular signaling molecule related autoinducer-2 from V. haveyi. Nevertheless, they seem to be unable to produce homologues of acyl-homoserine lactones. Furthermore, Escherichia coli DH5alpha can be complemented by the introduction of a P. gingivalis gene with high homology to the luxS gene, which has been called luxS(P.g.).