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目的:比较侵袭性牙周炎（aggressive periodontitis，AgP）、慢性牙周炎（chronic periodontitis，CP）与牙周健康者（periodontally healthy，PH）龈下菌群的差异，为牙周病的病因学研究及基于菌群调控的牙周病新疗法提供参考。方法:按纳入标准收集2013年12月至2014年12月在南京大学医学院附属口腔医院·南京市口腔医院牙周病科门诊就诊的AgP（AgP组）、CP（CP组）患者和PH受试者（PH组）各10例，根据X线片和口内情况初步预估取样位点后，收集各组龈下菌斑并记录各项牙周临床指数，提取龈下菌斑样本中的DNA，PCR扩增、构建DNA文库并对16S rDNA测序。最终可成功构建文库并测序者包含：8例AgP患者的18个样本，10例CP患者的31个样本和8名PH志愿者的10个样本。对各组样本的α多样性和β多样性以及菌群构成进行分析和比较，并采用Pearson相关性分析评价细菌与探诊深度的相关性。结果:菌群分析显示，AgP组龈下菌群的α多样性显著低于其他两组（n P<0.05）。在门水平，AgP和CP组拟杆菌门丰度[分别为（36.8±7.4）%、（37.2±6.3）%]、螺旋体门丰度[分别为（16.0±5.4）%、（11.8±3.6）%]均显著高于PH组[分别为（27.5±11.2）%、（5.2±4.4）%]（n P<0.05），而放线菌门和变形菌门丰度[AgP组分别为（4.2±3.3）%、（12.9±5.1）%；CP组分别为（6.1±2.6）%、（12.1±4.0）%]均显著低于PH组[分别为（19.3±13.1）%、（23.0±10.1）%]（n P<0.01）；AgP组龈下菌群中螺旋体门和柔壁菌门的丰度[分别为（16.0±5.4）%、（1.7±1.2）%]均显著高于CP组[分别为（11.8±3.6）%、（0.7±0.6）%]（n P<0.05）。在属水平，AgP组龈下菌群中棒状杆菌属、放线菌属、n Saccharibacteria_norank、月形单胞菌属、n Oribacterium的丰度显著低于CP组，而产线菌属、n Lentimicrobiaceae_norank、n Defluviitaleaceae_UCG_011、n Family_XI_unclassified的丰度显著高于CP组(n P<0.05）。主坐标分析显示，各组样本存在聚类现象。线性判别分析显示，AgP组富集菌包括螺旋体科等，CP组富集菌包括拟杆菌科等。相关性分析显示，AgP组中密螺旋体属、n Defluviitaleaceae_UCG_011、支原体属、卡氏菌属、n Fretibacterium的丰度与探诊深度呈显著正相关（n r=0.525~0.750，n P<0.05），丛毛单胞菌科-未分类的属、链球菌属、二氧化碳噬纤维菌属、奈瑟菌属、普雷沃菌属、消化球菌属、劳尔菌属、n Bergeyella和放线菌属的丰度与探诊深度呈显著负相关（n r=-0.617~-0.490，n P<0.05）；CP组小类杆菌属、n Family_XI_unclassified、卡氏菌属、消化链球菌属、n Pelospora和理研菌科_RC9_肠组的丰度与探诊深度呈显著正相关（n r=0.430~0.533，n P<0.05）。n 结论:牙周炎症和健康时其龈下菌群存在明显不同；AgP和CP的龈下菌群也存在明显差异，提示这可能是两种不同的疾病。“,”Objective:To compare the subgingival microbiota of subjects from patients with aggressive periodontitis (AgP), chronic periodontitis (CP) and periodontally healthy (PH) individuals, respectively.Methods:Volunteers were recruited from the Nangjing Stomatological Hospital, Medical School of Nanjing University during December 2013 to December 2014. Ten individuals were included in each of three groups. Preliminary estimation of sampling sites was chosen based on the X-ray and intraoral examination. Then the subgingival plaque samples were collected, the periodontal clinical indices were recorded, genes were extracted and amplified by PCR, and subsequently a DNA library was constructed for 16S rDNA sequencing. The library that can be successfully constructed and sequenced includes: 18 samples from 8 AgP group patients, 31 samples from 10 CP group patients and 10 samples from 8 PH group volunteers. Finally, we analyzed and compared the α-diversity, β-diversity and microbial compositions of samples in each group. Pearson correlation analysis was adopted to evaluate the correlation between the relative abundance of microorganisms and the probing depth (PD).Results:The α-diversity of subgingival flora in AgP group was significantly lower than that in PH group and CP group, respectively ( n P<0.05). On the phylum level, the abundance of n Bacteroides [(36.8±7.4)%] and n Spirochetes [(16.0±5.4)%] in AgP group and the abundance of n Bacteroides [(37.2±6.3)%] and n Spirochetes [(11.8±3.6)%] in CP group were significantly higher than those in PH group [(27.5±11.2)%, (5.2±4.4)%, respectively, n P<0.05]. While the relative abundance of n Actinomycetes and n Proteobacteria [(4.2±3.3)%, (12.9±5.1)%, respectively] in AgP group and that of CP group [(6.1±2.6)%, (12.1±4.0)%, respectively] were significantly higher than PH group [(19.3±13.1)%, (23.0±10.1)%, respectively,n P<0.01). The abundance of n Spirochetes and n Tenericutes in AgP group [(16.0±5.4)%, (1.7±1.2)%, respectively] were significantly higher than that in CP group [(11.8±3.6)%, (0.7±0.6)%, respectively, n P<0.05]. At the genus level, n Corynebacterium, Actinomycete, Saccharibacteria_norank, Selenomonas and n Oribacterium in the subgingival flora of AgP group were significantly lower than that of CP group, while the relative abundance of n Actinomycetes, Lentimicrobiaceae_norank, Defluvitaleaceae_UCG_011, Family_XI_unclassified were significantly higher than that of CP group (n P<0.05). Principal coordinate analysis showed that samples of each group clustered separately from each other. Linear discriminant analysis revealed that the bacteria enriched in AgP group included n Spirochetes, while in CP group included n Bacteroidaceae. The result of correlation analysis showed that the abundance of the following genera in AgP group were positively correlated with PD: n Treponema_2, Defluitaleaceaeae_UCG_011, n Mycoplasma, n Catonella, Fretibacterium (n r=0.525-0.750, n P<0.05). While the relative abundance of n Comamonadaceae_unclassified, Streptococcus, Capnocytophaga, Neisseria, Prevotella, Peptococcus, Ralstonia, Bergenia and n Actinomycetes were negatively associated with PD (n r=-0.617--0.490, n P<0.05). In the CP group, the abundance of n Dialister, Family_XI_unclassified, Catonella, Peptococcus, Pelospora and n Rikenella_RC9_gut group were positively correlated with PD (n r=0.430-0.533, n P<0.05).n Conclusions:There is a clear difference between the subgingival flora of periodontal patients and that of PH individuals. Besides, subgingival flora of AgP and CP are also different, suggesting that these could be two different diseases.