Microbial Diversity Analysis On Dental Plague In Healthy Adults And Dental Caries

Objective:Dental caries is one of the most common chronic diseases which do harm to human oral health,and is a bacterial infectious disease caused by mutiple microbiota.The present study aimed to comprehensively understand the microbial diversity and shift of dental plaque in healthy adults and dental caries,to determine whether the presence of plaque core microbiome,to identify the microbiota or key players related to oral health and dental caries.And thus will provide new therotical basis and direction for caries etiology,prevention and control.Methods:In strict accordance with the inclusion and exclusion criteria,160 adult healthy and caries subjects were chosen and divided into 4 groups according to DMFT: high caries(HC),moderate caries(MC),low caries(LC)and no caries(NC).Supragigival dental plaque samples were collected from each subject.The bacterial genomic DNA were extracted and pyrosequenced on high-throughput Roche 454 FLX+ platform by amplifications of 16 S rDNA V1-V3 hypervariable region.The obtained sequences were used for bioinformatic analysis.Results:A total of 2261700 high-quality sequences were produced and clustered into 10365 operational taxonomic units(OTUs).These OTUs were classified into 453 independent species,belonging to 122 genus,66 families,34 orders,21 classes and 12 phyla.The smooth rarefaction curves suggested that our sequencing efforts were enough to reflect the plaque microbial diversity.The ? diversity analysis showed that the healthy plaque microbial diversity was higher than that of dental caries,and with the severity of caries increased the diversity decreased gradually.The Venn diagram showed that the four groups shared 7522 OTUs,indicating the presence of plaque core microbiome.The dominant phyla of plaque microbiota incuded Bacteroidetes,Actinobacteria,Proteobacteria,Firmicutes,Fusobacteria and TM7,the dominant genera including Capnocytophaga,Prevotella,Actinomyces,Corynebacterium,Neisseria,Streptococcus,Rothia,Leptotrichia,TM7_[G-1].The heatmap and principal coordinate analysis displayed that the plaque microbial community structure of the four groups was similar,the bacterial members among groups were relatively constant,only showing the differences in species abundance.By means of variance analysis and LSD multiple comparison to find significant differences of bacterial abundance between groups,the results showed that Fusobacteria and GN02 were health-related,Firmicutes,Tenericutes and Synergistetes were caries-related.In addition,the results identified 10 health-related genera and 21 caries-related genera.According to the PLS-DA analysis,27 potential key genera that could lead to the different distribution of microbiota between healthy and caries were identified,including 6 caries-related genera and 7 health-related genera.Conclusions : 454 pyrosequencing provides abundant bioinformatic information for the microbial diversity analysis on dental plague in adults.The healthy plaque microbial diversity is higher than that of dental caries,and with the severity of caries increases the diversity decreases gradually.The plaque core microbiome is confirmed.A large number of health-related and caries-related microorganisms and key genera are identified,which can provide biomarkers for the health and caries risk assessment.This study supports that dental caries is a polymicrobial dysbiosis disease,treatment strategies directed toward modulating microbial interactions and/or their functional output should be further developed.