Mutans streptococci and other caries-associated acidogenic bacteria in five-year-old children in South Africa.

Correlations between mutans streptococci and caries are inconsistent; some studies show that early caries may occur with other bacterial species possessing the ability to survive, interact and compete with mutans streptococci. This study looked at the relationship between mutans streptococci, Lactobacillus, Actinomyces and Veillonella in saliva and plaque collected from four tooth sites in two ethnic groups, with and without caries. All samples were collected and cultured onto selective media. Colonies were enumerated and identified using biochemical tests. Pearson correlations showed low yet statistically significant correlations between plaque mutans streptococci counts and the number of decayed surfaces (ds) and decayed, missing and filled surfaces (dmfs) of primary teeth in blacks and in coloreds (historical race classification). Salivary mutans streptococci counts correlated with ds and dmfs in coloreds. No relationship was found between ds, dmfs and Lactobacillus, Actinomyces or Veillonella numbers. Significant associations were evident between plaque mutans streptococci and Veillonella and Lactobacillus in black children with caries and between plaque mutans streptococci and Actinomyces and Lactobacillus and Veillonella in colored children. Hence, oral microbes are in constant flux but have interrelationships in children with caries.