Abstract
Viridans streptococci, including the anginosus, mitis, mutans, and salivarius groups, dominate oral microflora that consists of more than 300 species of bacteria, and are considered to be the principal indigenous microbiota in the human oral cavity. Among these, mutans streptococci are closely associated with the development of human dental caries. Mitis group streptococci, which have been identified in pre-dentate infants, are associated with infectious endocarditis and sepsis. Since dental plaque, which is biofilm in human oral cavity, is a mass of these bacteria, it is thought to be a hotbed of the above diseases. It is meaningful to resolve the mechanism of dental plaque formation and to identify the organism in dental plaque. Therefore, we have studied about the molecular analyses of glucosyltransferase, which plays an important role in the formation of plaque biofilm, and the phylogenetic analyses of streptococcal gtf genes,16 S-23 S rRNA intergenic spacer genes, and four housekeeping genes. Then from these results, we have developed the molecular and phylogenetic methods to detect and identify these streptococci, rapidly and precisely.
