Surface-associated properties of Actinomyces strains and their potential relation to pathogenesis

Twenty-nine strains from the Actinomyces species were tested for a range of surface properties. Results show considerable heterogeneity both between different species and within some of the species, especially Actinomyces naeslundii. Two commonly used A. naeslundii strains, T14V and ATCC 12104, fell within the low (salivary aggregation and collagen binding by T14V), moderate (surface charge and haemagglutination) or high range of values (hydrophobicity, saliva-coated hydroxyapatite adhesion, polystyrene binding by T14V, fibrinogen binding by T14V and collagen binding by A. naeslundii ATCC 12104). Both strains adhered well to saliva-coated hydroxyapatite; T14V bound the highest amount of fibrinogen, ATCC 12104 had the highest number of cells bound to collagen and T14V was not bound at all. The heterogeneity of these characteristics highlights the need to include a range of strains of Actinomyces in studies on their pathogenicity. Statistical correlations were found between a number of properties, for example saliva-coated hydroxyapatite adhesion and hydrophobicity, and between haemagglutination and hydrophobicity.