Analysis supragingival plaque bacterial community of different caries susceptibile children

Objectives: To survey bacterial diversity in supragingival plaque and its association with dental caries by denaturing gradient gel electrophoresis (DGGE). Methods: 12 Chinese pre-school children were selected in this study, 4 in caries-free group (CF, dmfs=0), 4 in caries-moderate group (CM, 4≤dmfs≤6) and 4 in caries-susceptible group (CS, dmfs≥10). Bacteria were directly isolated from the dental plaque and extracted DNA from these uncultured bacteria. DGGE was performed to separate the variable V3~V5 region of 16S rDNA PCR products. DGGE bands were excised from the gels for sequencing and identification. Results: A total of 34 species of different culture-independent bacteria were isolated and classified according to phylogenetic analysis. Of these species, those belonging to Oralis streptococus°¢Mutans streptococus°¢Actinomyces°¢Capnocytophaga°¢Campylobacter°¢Burkholderia°¢Neisseria°¢Leptotrichia°¢Haemophilus°¢Prevotella and Corynebacterium. The genetic diversity of the dental plque microbiota was significantly higher in caries-free group (CF, dmfs=0)°¢caries-moderate group (CM, 4≤dmfs≤6) than in caries-susceptible group (CS, dmfs≥10),P<0.05. Conclusion: Here we report a 16S rDNA-based comparative survey of the bacterial community in the supraginvial plaque associated with children caries.The Oralis streptococus and Campylobacter were absent in the CS Group and associated with health, while bacteria of Mutans streptococus and Actinomyces were detected in all tested dental plaque and may play an important role in caries initiation and development.