Interbacterial binding among strains of pathogenic and commensal oral bacterial species.

Strong interspecies adherence was demonstrated among the periodontal pathogens Treponema denticola, Bacteroides forsythus and Porphyromonas gingivalis, and between these pathogens and the commensal plaque organism Streptococcus crista. Adherence showed specificity and demonstrated saturation binding kinetics. Binding between B. forsythus and P. gingivalis appeared to be a unimodal protein-protein interaction. Binding between the other organisms was at least bimodal involving interactions between combinations of proteins and carbohydrates with a variety of sugar specificities. Salivary molecules prevented adherence between T. denticola and S. crista, and serum eliminated B. forsythus binding to P. gingivalis. All other interactions occurred to some degree in the presence of serum and saliva. Such interbacterial binding interactions may be important in the establishment of periodontopathic plaque.