Infrequent polysaccharide cohesion among Actinomyces viscosus and Actinomyces naeslundii fresh isolates of human origin

Abstract

Dextran‐mediated agglutination has been both proposed and opposed as a mechanism for cohesive interactions between Actinomyces viscosus and streptococci in dental plaques. In their Studies, opponents of this mechanism used laboratory strains subcultured in vitro for unknown periods, whereas its proponents had previously shown that laboratory passage of Actinomyces strains weakened this trait. To clarify this issue, eighty‐eight strains of A. viscosus and Actinomyces naeslundii freshly isolated from the human oral cavity and hardly subcultured in vitro, were studied for enhancement of agglutination by commercially obtained polysaccharides including dextran, inulin, agarose, and starch and polysaccharides isolated from sucrose‐grown Streptococcus mutans, Streptococcus sanguis, and Streptococcus salivarius. Few of the strains exhibited higher agglutination scores in buffer containing any of the various polysaccharides than in control buffer free of the polysaccharides. Infrequent polysaccharide agglutinability of these human isolates, even by polysaccharides likely to be encountered in dental plaques, casts doubt on this explanation for Actinomyces’cohesive interactions in plaque formation.

Glycogen Synthetic and Degradative Activities by Actinomyces viscosus and Actinomyces naeslundii of Root Surface Caries and Noncaries Sites

“…A. viscosus strain 262 and A. naeslundii strain 151 were originally isolated from the plaques over root surface caries lesions, whereas A. viscosus strain 251 and A. naeslundii strain 226 were ori ginally isolated from the plaques over intact root surfaces [Komiyama et al, 1986]. These strains have been kept in vials containing serum-coated glass beads at -70°C [Ellen et al, 1983], and have never been subcultured. Each strain was grown anaerobically (10% CO;, 10% H,.…”

Whole cell agglutination and dextran binding in oral Actinomyces species

“…In S. mutans, however, it has been reported that this property can be lost during laboratory passages. The above results did not agree with those of McBride and Bourgeau (1975) who reported that all A. viscosus strains, including human isolates, are equally sensitive to dextran-induced agglutination, but supported the finding that freshly isolated Actinomyces strains of human origin exhibited no significant agglutination in buffered dextran T2000 (Eiien, Fillery & Seckington 1983). Furthermore, Cisar, Kolenbrander and Mclntire (1979) have reported that rodent but not human strains of A. viscosus are agglutinated by dextran.…”

Glycogen Synthetic Abilities of Actinomyces viscosus and Actinomyces naeslundii Freshly Isolated from Dental Plaque over Root Surface Caries Lesions and Non-carious Sites

“…The broth culture was then transferred into several vials containing serum-coated glass beads and immediately frozen at -700C (Ellen et al, 1983). These frozen beads were always used to inoculate growth medium for each experiment, thus avoiding further laboratory passage of the original isolate.…”

“…However, there is little information on these aspects of oral Actinomyces, particularly fresh clinical isolates of this species. There has been some evidence to suggest that the physiology of laboratory strains may not resemble that of freshly isolated strains and may not be relevant to the in vivo state (Hamilton and Bowden, 1982;Ellen et al, 1983;Vadeboncoeur and Trahan, 1983). The purpose of the present study was to investigate relative glycogen synthetic abilities of A. viscosus and A. naeslundii freshly isolated from the dental plaque over intact root surfaces and over root surface caries lesions.…”