Microbial Diversity Analysis On Dental Plaque Of Caries-active Deciduous Teeth

Caries is a common oral disease. The quadruple factor theory believes that caries iscaused by bacteria, food, host and time together and the most dangerous factor isbacteria. There were over700microbes living in human mouth. However, over half ofthem cannot be cultured. Recently, molecular biotechniques based on16S rDNAhavebeen used widely in microbial community analysis, showing an innovative way formicrobial ecology study and promoting development of oral microbiology study.Objective: Based on the previous studys, the study chosed “caries-free children andcaries-active children”as subjects, metagenomic analyzed the dental plaque of6children from phlum, class, order, family to species(OTU)by454pyrosequencing(GS-FLX Titanium)with16S rRNA V1-V2hypervariable region PCR amplication,the ecology macrography debated the significant microbiome, tested the microbialdiversity of dental plaque and new avenues for therapeutic and the etiology of caries.Methods：The samples from3caries-active and3caries-free children were selectedaccording with WHO sampling standard．Take3specimens from each caries-activechildren (labial surfaces, lingual surfaces and lesions) and take2specimens from eachcaries-free children (labial surfaces and lingual surfaces)．The genomic DNAofdental plaque was extracted，PCR amplification of the V1-V2region of bacterial16SrDNA genes and the construction of library．Entrust a gene company to test sequenceof an established16S rDNAlibrary by the second generation high-throughputsequencing. These sequences were removed following the procedure and thenclassified by RDP classifier．The UCLUST software were used for bacterial diversity estimates．The statistical significance of differences in microbial communitycomposition was determined with clustering analysis and Metastats analysis.Results：(1) A total of5,261species-level OTUs were detected and assigned to9phyla,16classes,22orders，38families,59genera.(2)5genera were significantlydifferent in caries plaque group(p0.05), including Streptococcus、Filifactor、Solobacterium、Thermus、Brevibacillus.(3)5genera were significantly differentbetween the three groups (labial groups, lingual groups and lesions groups)(p0.05),including Streptococcus、Propionibacterium、Corynebacterium、Leptotrichia、Lactobacillus.(4)11genera were common in all15plaque samples and accounted forabout95%plaque reads, and at species-level (OTUs),126OTUs presented in allplaque samples.Conclusion:(1) By using the method of454pyrosequencing, the diversity of oralmicrobiota was very high, more bacteria were found;(2) there are same genera weresignificantly different between caries-free and caries-active samples, and in additionto Streptococcus mutans, other microbiota may contribute to caries development.