Bacterial profiles of oral streptococcal and periodontal bacterial species in saliva specimens from Japanese subjects

Objective: Recent developments in molecular biological techniques have increased understanding of the distribution of oral bacterial species in clinical specimens, though few investigations have been conducted to simultaneously detect oral streptococcal and periodontal species in the same specimens. The purpose of the present study was to investigate the distribution and correlation of 6 oral streptococcal and 6 periodontal species in saliva specimens taken from children and their mothers. Design: Seventy-four pairs of children and their mothers were approved to participate in this study. Saliva specimens were collected and bacterial DNA extracted, which was subjected to PCR analyses using species-specific sets of primers. The combinations of species able to be detected simultaneously were determined by statistical analyses. Results: Streptococcus sobrinus and Porphyromonas gingivalis were detected more often in the mothers than the children. Streptococcus mutans, Streptococcus sanguinis, and Streptococcus oralis were detected simultaneously in a significant number of specimens, while the presence of Campylobacter rectus was correlated with the presence of at least one of the red complex species (P. gingivalis, Treponema denticola and Tannerella forsythensis). On the other hand, no correlation was shown between the rates of detection of oral streptococcal and periodontal species. Conclusions: Our results indicate that among streptococcal and periodontal species, several are able to coexist in saliva, while the presence of both does not have an influence on each other.