The effect of indigenous bacterial populations on buccal epithelial cells on subsequent microbial adhesion in vitro

Despite the numerous investigations on the adhesion of microorganisms to buccal epithelial cells, it is difficult to correlate different results, as disparate adherence values have been reported for a given organism. As one reason for this disparity may be the indigenous or natural bacterial populations on human buccal epithelial cells, the effect of the latter on subsequent microbial adherence in vitro was examined. There was a highly significant correlation between the degree of natural bacterial colonization on pooled buccal epithelial cells from 8 healthy donors and the adhesion of a single isolate each of Streptococcus mitis, Escherichia coli and Actinomyces naeslundii. However, no such relationship could be established for Candida albicans, Streptococcus milleri and another isolate of Streptococcus mitis. As in previous studies, variation in adherence values was found, both between samples from different donors, and from the same donor over time, but to a far lesser degree in pooled samples from different donors. These results imply that natural bacterial populations on buccal epithelial cells may affect the adhesion values derived from laboratory experimentation, and hence such data should be interpreted with caution.link_to_subscribed_fulltex

In vitro modulation of oral bacterial adhesion to saliva-coated hydroxyapatite beads by milk casein derivatives

Bovine caseinate, derivatives of its glycosylated moiety [caseinoglycomacropeptide (CGP)], and caseinophosphopeptides were evaluated as inhibitors of adhesion of oral bacteria to saliva‐coated hydroxyapatite beads (S‐HA). All milk casein‐derived components behaved as potent inhibitors of Streptococcus sanguis OMZ 9 and Streptococcus sobrinus OMZ 176 adhesion to S‐HA, whereas neither bovine serum albumin nor polyethyleneglycol were able to interfere with the adhesion of these strains. By contrast, none of the molecular species tested was able to inhibit the attachment of Actinomyces viscosus Ny 1 to S‐HA. On the other hand, casein derivatives were shown to displace human serum albumin from S‐HA beads. They were also able to bind to the bacterial cell surface of all strains examined. Collectively, these findings suggest that interactions between acidic casein‐derived milk components and the biological surfaces involved in bacterial adhesion to S‐HA result in an inhibitory effect that is selective for the oral streptococci examined. </p