ADHESIVE PROPERTIES OF VIRIDANS STREPTOCCOCAL SPECIES

Seventy-one strains of viridans streptococci, classified as Streptococcus sanguis, S. gordonii, S. oralis, S. mitis or S. anginosus by a revised taxonomic scheme, were characterized and compared by their specific adhesive properties. The frequency of bacterial adhesion to saliva-coated hydroxyapatite (SHA) was greater among strains of S. sanguis, S. gordonii and S. oralis than among those of S. mitis and S. anginosus. Similarly, the expression of sialic acid reactive adhesins, detected by neuraminidase sensitive bacterial haemagglutination, was noted more frequently with strains of S. sanguis (19 of 21), S. gordonii (14 of 16) and S. oralis (8 of 11) than those of S. mitis (2 of 12) and S. anginosus (0 of 11). Most strains of S. gordonii (14 of 16) and S. oralis (7 of 11) also aggregated acidic proline rich protein-coated latex beads, but this activity was observed rarely with strains of S. sanguis (2 of 21), & mitis (1 of 12) and & anginosus (0 of 11). Strains of S. anginosus (6 of 11) participated in lactose resistant coaggregations with actinomyces in coaggregation groups A (e.g. Actinomyces viscosus T14V-J1) and B (e.g. A. naeslundii WVU45). Lactose resistant coaggregations were also observed between strains of & gordonii (9 of 16) and actinomyces in coaggregation group A. Lactose sensitive coaggregations occurred between actinomyces and each of 11 S. oralis strains but less frequently with strains of S. sanguis (6 of 21), & gordonii (3 of 16), S. mitis (3 of 12) and S. anginosus (1 of 11). Certain streptococcal strains with receptors for the lactose sensitive lectins of actinomyces, including 9 of 11 S. oralis, also coaggregated frequently with strains of either S. sanguis (10 of 21) or S. gordonii (9 of 16). Further studies with representatives of these latter three streptococcal species suggested that the streptococci with receptors for the GalNAc sensitive lectins of S. sanguis and S. gordonii were those with GalNAcbeta1 --> 3Gal- rather than Galbeta1 --> 3GalNAc-containing cell wall polysaccharides.