中文摘要：

目的探讨人肠道柔嫩梭菌（Clostridium leptum，C．leptum）类群与慢性牙周炎和2型糖尿病的相关关系。方法收集慢性牙周炎患者（CP组）、2型糖尿病患者（DM组）、伴2型糖尿病的慢性牙周炎患者（DM＋CP组）及健康对照者（HC组）各20例的粪便标本。根据cleptum类群16SrRNA序列设计特异性引物，以常规PCR产物经克隆后的质粒DNA为标准品，经梯度稀释后制备标准曲线。待测粪便标本提取细菌基因组DNA，应用实时定量PCR方法对cleptum类群进行定量分析。结果4组标本每克湿便中C．1eptum类群的16SrRNA基因拷贝数的对数值（10gcopies／g）：HC组（7．09±0．17）、CP组（6．31±0．58）、DM组（5．79±0．52）、DM＋CP组（5．41±0．29）。与HC组相比，其他三组C．leptum类群基因拷贝数均明显减少（P〈0．05）。结论C．leptum类群可能与慢性牙周炎和2型糖尿病的发生、发展相关。

英文摘要：

Objective To investigate the relationship between Clostridium leptum （ C. leptum） subgroup in the human gut, the periodontal disease and type 2 diabetes mellitus. Methods Fresh fecal samples were obtained from twenty patients with chronic periodontitis （CP group）, twenty patients with type 2 diabetes mellitus （DM group）, twenty patients with chronic periodontitis complicated by type 2 diabetes [ （DM ＋ CP） group] and twenty healthy control subjects （HC group）. Genus-specific primer of C. leptum subgroup was designed for 16S rRNA-targeted PCR. The standard curve of real-time quantitative polymerase chain reaction （RTQ-PCR） was generated from a grade-dilution of plasmid DNA which was cloned from PCR products. Bacterial genome DNA extracted from fecal samples was quantified by RTQ-PCR to analyze C. leptum subgroup amounts. Results Logarithm for 16S rRNA gene copies of C. leptum subgroup per gram feces in HC group, CP group, DM group and （DM ＋ CP） group were （7.09 ±0. 17）, （6.31 ±0.58 ）, （5.79 ± 0.52） and （5.41 ± 0.29 ）, respectively. Compared with HC group, the logarithm of the other three groups were dramatically decreased （ P 〈 0.05 ）. Conclusion C. leptum subgroup may be associated with the development and progression of chronic periodontitis and type 2 diabetes mellitus.