Isolation of acid producing sorbitol-adapted bacteria from dental plaque using selective agar media

Acidogenic bacteria metabolizing sorbitol were isolated and identified from dental plaque of twenty nine volunteers, claiming to be users (sixteen) and non-users (thirteen) of sorbitol-containing chewing gum and candy. Sixty bacterial strains were isolated, using improved selective agar media. The taxonomy of twenty strains, all Gram-positive cocci, was determined employing a customized BBL MinitekR system and other biochemical reactions. The majority of these strains represented Streptococcus sanguis and Streptococcus acidominimus. Although sorbitol-metabolizing bacteria were found in plaque specimens of most persons tested, a larger number of acidogenic sorbitol degrading bacteria was detected in the plaque of the volunteer group claiming to use sorbitol-containing sweets. Bacteriological results indicate that frequent consumption of sorbitol-containing products will lead to a shift in oral ecology, numerically favouring sorbitol-metabolizing bacteria. These sorbitol adapted bacteria appear to be as acidogenic as Streptococcus mutans in the presence of ordinary sugars.