Detection of Streptococcus Mutans in Human Saliva and Plaque using Selective Media, PCR, and Monoclonal Antibodies

Background: The purpose of this study was to evaluate the distribution of dental caries-associated Streptococcus mutans in human saliva and plaque.

Methods: Samples were collected from 90 subjects (30 children, 30 adolescents, and 30 adults). The decayed, missing, and filled teeth (DMFT) and Significant Caries (SiC) indices were assessed. PCR analysis was utilized to detect Streptococcus mutans in each sample. Enumeration of Streptococcus mutans was conducted by cultivation on Dentocult-SM^® and mitis salivarius agar medium or, for saliva samples, by enzyme-linked immunosorbent assay analysis using monoclonal antibodies specific to antigen I/II and glucosyltransferase.

Results: PCR analyses detected S. mutans in 79.7% and 56.8% of all saliva and plaque samples, respectively. S. mutans was detected in 59.1%, 88.0%, and 88.9%, and in 86.4%, 56.0%, and 33.3% of saliva and plaque samples from children, adolescents, and adults, respectively. There were significantly higher levels of Streptococcus mutans in the saliva of adolescents than other groups. There was a positive correlation between DMFT and the level of Streptococcus mutans reactivity measured by ELISA.

Conclusions: Our results suggest oral hygiene should be emphasized in adolescents more than in children or adults, and this group should be targeted for early prevention and research of dental caries.