基于16S rRNA基因序列分析1例健康人龈上菌群

The composition of supergingival plaque of one healthy subject based on analysis of 16S rRNA sequence

目的构建细菌16S rRNA基因文库分析健康人龈上菌群的组成。方法取1例健康成年女性龈上菌斑并构建细菌16S rRNA基因文库,分析其龈上菌群组成。结果 1例健康人龈上菌斑细菌的种水平分类有62种,其中可以培养的细菌有34种而尚无法培养的细菌有28种(45.1%);新发现的细菌物种有17种(27.4%);缓症链球菌是克隆子数最多的优势菌种;链球菌属、奈氏菌属和嗜血杆菌属占文库的60%,为主要菌群;构建的细菌16S rRNA基因文库的覆盖率为95%,文库的均匀度值为0.016。结论 1例健康人龈上菌群中45.1%的细菌尚无法分离培养、27.4%的物种尚不清楚,未培养菌及尚不清楚的菌种中可能藏匿着与口腔疾病密切相关的致病菌,全面地了解健康人龈上菌群的组成有助于研究龋病的发病机制。

Objective To characterize the supergingival plaque composition of one healthy adult by using culture-independent methods.Method 16S rRNA gene clone libraries were utilized to survey the supergingival plaque composition in one healthy individual.Result 62 species-level operational taxonomic units（OTU） were identified in the oral microflora of the subject.Of the 62 OTUs,34 OTUs belong to culture-defined bacterial species and 28 OTUs were non-cultivatable phylotypes.Over 45.1% of the bacterial flora was represented by not-yet-cultivated phylotypes.17 OTUs were classified as unknown phylotypes,accounted for about 27.4% of the bacteria.The coverage was 95% for the 16S rRNA gene sequences set and the evenness was 0.016.Streptococcus mitis was the dominant specie that has the most clones.Streptococcus,Neisseria and Haemophilus accounted for 60% of the total sequences;and they were the keystone group in the supergingival plaque of the subject.Conclusion Over 45.1% of the bacterial flora in the individual case are not-yet-cultivated phylotypes.27.4% of OTUs are unknown phylotypes. It is important to fully define the supergingival microflora of the healthy subject before we can understand the role of bacteria in caries.