Relative Adherence of Bacteroides Species and Strains to Actinomyces viscosus on Saliva-coated Hydroxyapatite

Abstract

The study was designed to compare the adherence of several Bacteroides species to A. viscosus. Using ³H, we labeled 24 laboratory strains, including 13 Bacteroides species and I I fresh clinical isolates of three Bacteroides species. Their adherence to A. viscosus bound to a saliva-coated mineral surface was quantified by liquid scintillation. Adherence relative to a standard strain, B. gingivalis 2561, was compared. Among the lab bacteroides, those of B. gingivalis (eight strains) were the greatest binders (mean, 80.5 ± 12.4%). Strains of other lab bacteroides bound less well (mean, 33.4 ± 6.3%). The difference in means was statistically significant (p<0.01). The mean for B. gingivalis strains was also significantly greater than that for strains of B. intermedius (51.7 ± 6.2%). Attachment of B . gingivalis was saturable in experiments in which either input concentration or time was the independent variable, indicating that B. gingivalis cells do not accumulate in this in vitro simulation of plaque formation by binding to each other. Subculture did not seem to affect the degree of binding.