目的：探讨肥胖者口腔唾液微生物的特点，比较肥胖者与正常体重者口腔唾液微生物组成、基因功能及代谢通路上的差异。方法：研究纳入无全身系统性疾病、无牙周炎及口腔黏膜病的肥胖者及性别、年龄相匹配的正常体重者，收集研究对象的非刺激性唾液。提取唾液样本DNA，用高通量测序方法进行宏基因组分析，结果经数据质控后进行物种分类及注释，差异物种线性判别分析（linear discriminant analysis， LDA），基因预测，基因集构建和功能注释分析。结果：过滤后每个样本得到可分类的、细菌的DNA序列平均条数为2 630 428。唾液微生物群落共包括 11个菌门、19个菌纲、26个菌目、41个菌科、62个菌属和164菌种。肥胖组与正常体重组微生物群落的优势菌门相同，为变形菌门、厚壁菌门、拟杆菌门、放线菌门和梭杆菌门，两组在纲、目、科、属、种等分类水平上均发现相对丰度差异具有统计学意义的物种。在纲水平上，Negativicutes纲和丹毒丝菌纲（Erysipelotrichia）丰度在肥胖组中的相对丰度高于正常体重组（P<0.05），黄杆菌纲（Flavobacteriia）和Bateroidetes纲在肥胖组中的相对丰度低于正常体重组（P<0.05）。9个菌属在两组间丰度差异具有统计学意义；种水平上，16个菌种的丰度差异具有统计学意义，其中产黑色素普雷沃氏菌（Prevotella melaninogenica）、唾液普雷沃氏菌（Prevotella salivae）、Solobacterium moorei和极小阿托波氏菌（Atopobium parvulum）等在肥胖组中相对丰度高于正常体重组（P<0.05），而血链球菌（Streptococcus sanguinis）在正常体重组中相对丰度高于肥胖组（P<0.05）。对基因预测结果进行分析，发现肥胖组样本基因数目较正常体重组多，差异有统计学意义（P<0.05），其中与营养和能量代谢、环境信息处理、人体疾病等通路相关的基因在肥胖组唾液样本中显著富集（P<0.01）。结论：肥胖者与正常体重者的口腔唾液微生物在物种组成、基因数目及代谢通路上均存在差异，值得今后扩大样本量进一步研究。

Objective： To investigate the characterization of the salivary microbiome in people with obesity and the differences in microbial composition, gene function and metabolic pathways of salivary microbiome between people with obesity and normal weight controls. Methods: The study was carried out in people with obesity and age- and sex-matched normal weight controls. None of these selected participants had the systemic disease, oral mucosal disease or periodontal disease. Unstimulated saliva samples were collected and oral examination was conducted. DNAs from saliva samples were extracted and sequenced in an Illumina NextSeq 500 platform. Community composition, linear discriminant analysis of taxonomic differences，gene prediction, gene set construction and annotation of gene function were performed. Results: The classified bacterial reads of the samples were 2，630，428 for each sample. A total of 11 phyla, 19 classes, 26 orders, 41 families, 62 genera and 164 species were detected ultimately. All samples had the same predominant phyla (Proteobacteria, Firmicutes, Bacteroidetes, Actinobacteria and Fusobacteria). There were statistical differences between the groups at the class, order, family, genus and species levels. At the class level, Negativicutes and Erysipelotrichia were more abundant in the obesity group, while Flavobacteriia and Bateroidetes dominated in normal weight group （P<0.05）. At the species level, 16 showed significant differences in relative abundance among the groups, in which Prevotella melaninogenica，Prevotella salivae，Solobacterium moorei and Atopobium parvulum ware more abundant in the obesity group, whereas Streptococcus sanguinis dominated in normal weight group (P<0.05). The people with obesity had a higher number of salivary microbial genes (P<0.05). We produced statistics on gene prediction and found salivary microbiome of obesity group had a higher number of genes (P < 0.05). Genes associated with the pathways of metabolism and environmental information processing and human diseases were significantly enriched in the saliva samples of people with obesity (P < 0.01). Conclusion: Significant differences were seen in composition, gene function and metabolic pathways of salivary microbiome between people with obesity and normal weight people. We hope to go on further study with larger sample size in the near future.