Cellular coaggregation of oral Streptococcus milleri with actinomyces

Abstract

Oral isolates of Streptococcus milleri were examined for their ability to coaggregate with actinomyces. Of the 68 S. mileri strains tested, including 3 reference strains, 40 strains coaggregated with Actinomyces naeslundii WVU45 (actinomyces coaggregation group B) and 36 strains coaggregated with Actinomyces viscosus T14V (actinomyces coaggregation group A). AU S. milleri strains of serotypes b (4 strains), e (2 strains), and f ( 24strains) coaggregated with both of the actinomyces. The coaggregation reactions between the S. milleri cells and A. naeslundii WVU45 cells were optimal at about pH 7.0 and were Ca2+ or Mg2+ dependent, but they were not inhibited by the presence of simple sugars or amino sugars, including lactose (up to 0.5 M). Treatment of the S. milleri cells with heat (100°C, 3 min) or proteases (trypsin, 1.0 mg/ml; pronase, 0.25 mg/ml; 37°C; 3 h) and of the actinomyces cells with periodate (0.01 M, 4°C, 16 h) destroyed their coaggregating abilities. The coaggregations between cells of the S. milleri strains, as well as cells of the Streptococcus sanguis Hi (reference strain for streptococcus coaggregation group 2) and the actinomyces strains (WVU45 and T14V), were inhibited by AFH1 (a carbohydrate receptor on T14V cells for a lectin on Hl cells). These interactions were also inhibited by anti-AFHl immunoglobulin G (IgG) and by anti-b, anti-e, and anti-f S. milleri IgG or anti-f IgG Fab fragments. These results suggest that S. milleri, at least strains of serotypes b, e, and f, belongs to streptococcus coaggregation group 2.

Lactose-sensitive and -insensitive cell surface interactions of oral Streptococcus milleri strains and actinomyces

“…Recently, we have isolated many strains of serotypes other than b, e, and f/F from the mouths of children (16). By employing these strains, the present studies confirm and extend the previous findings regarding the coaggregation of S. milleri with actinomyces (5,14) which is not inhibited by lactose. Certain oral S. milleri strains exhibit coaggregation which is inhibited by lactose.…”

“…Our previous studies demonstrated that large numbers of Streptococcus milleri isolates from human mouths (15,17) coaggregate with cells of actinomyces coaggregation groups A and B and that all belong to serotype b, e, or f/F (5). The coaggregation reactions of these S. milleri strains are not inhibited by lactose and are mediated by streptococcal adhesins and actinomyces carbohydrate receptors, suggesting that these strains belong to streptococcus coaggregation group 2.…”

“…The coaggregation reactions of these S. milleri strains are not inhibited by lactose and are mediated by streptococcal adhesins and actinomyces carbohydrate receptors, suggesting that these strains belong to streptococcus coaggregation group 2. It was also shown that a few strains of the other serotypes produce different patterns of coaggregation with the actinomyces cells (5), but their coaggregation reactions have not been characterized in detail to date. Recently, we have isolated many strains of serotypes other than b, e, and f/F from the mouths of children (16).…”

“…The conditions of bacterial growth have been described previously (5). Briefly, cells were cultured anaerobically in Todd-Hewitt broth (BBL Microbiology Systems, Cockeysville, Md.)…”

Sensitivity of bacterial coaggregation to chelating agents

“…There are several approaches to disaggregating cell clumps, including antibodies, antibiotics, chaotropes, enzymes and low molecular mass saccharides complementary to lectins. Experiments performed some years ago by Cisar et al [7], McIntire et al [8], Kolenbrander et al [9] and Eifuku et al [10] suggest that adhesins of Actinomyces spp. may be inhibited by chelating agents, such as EDTA.…”