Phenotypic and genotypic characterization of Thai oral streptococci, lactobacilli and pediococci

This work was to assess the isolation and identification of Thai oral bacteria. Seventeen viridans group streptococci (VGS) and seventeen lactic acid bacteria from saliva were characterization based on their morphological, physiological and biochemical characteristics and the 16S RNA gene sequences analysis. The Gram-positive cocci in chains of viridans group comprised of six isolates (Group I) were identified as Streptococcus gordonii, 6 isolates (Group II) were Streptococcus salivarius, 4 isolates (Group III) were Streptococcus sanguis and one isolate (Group IV) was Streptococcus mutans. Seventeen lactic acid bacterial isolates were Gram-positive and catalase negative. They did not contained diaminopimelic acid in the cell wall peptidoglycan. They were divided into four groups, the rod-shaped in Group A (11 isolates) and Group B (2 isolates) which were identified as Lactobacillus fermentum and Lactobacillus salivarius, respectively. The tetrad-forming cocci in Group C (3 isolates) and Group D (1 isolate) were identified as Pediococcus acidilactici and P. pentosaceus, respectively.