从复杂的肠道菌群中识别关键菌，鉴定其功能，是人体微生物组研究的重要内容。课题组近期开展广东省肠道菌群与慢性病调查，通过随机分层抽样八千余社区人群，发现Ralstonia是NAFLD显著相关菌属之一，高低Ralstonia两组人群NAFLD患病率相差十倍。Ralstonia在广东省人群肠道普遍存在，但在西方人群检出率低，相关研究少。假设：肠道Ralstonia与NAFLD存在因果关系，是本地人群NAFLD重要风险因子。本课题拟通过无菌鼠定植实验，验证Ralstonia与NAFLD的因果关系；检测慢性炎症、断食诱导脂肪因子、乙醇、三甲胺等通路，探索其潜在作用途径；在前期人群横断面调查基础上，建立随访队列，比较罗尔斯顿菌高低两组五年NAFLD新发率，探明其相对危险度。本研究有望阐明罗尔斯顿菌是否为一类独特的促进本地人群NAFLD的关键菌，为NAFLD风险评价及预防干预提供新靶点。

Identifying key species from the complex gut microbiota and studying its function is a major task in the microbiome research field. Recently, our group completed Guangdong Gut Microbiome Project, which surveyed around eight thousand subjects using random sampling, and identified that gut Ralstonia was highly correlated with non-alcoholic fatty liver disease (NAFLD). Ralstonia is rarely detected in Western populations, so its research is highly limited. We hypothesize that: Ralstonia in human gut microbiota can causally aggravate host NAFLD and therefore can increase disease risk. In the present study, we ought to examine the cause-effect relationship between gut Ralstonia and host NAFLD in germ-free mice. Chronic inflammation, FIAF, ethanol and TMA pathways will be examined to explore mechanisms. Meanwhile, a follow-up study will be conducted to examine if individuals with higher Ralstonia would have significantly higher risk of developing NAFLD compared to those with lower Ralstonia in their gut. This study aims to identify a unique gut bacterial species that promotes host NAFLD in the local population, therefore offers a new target in the prognosis and treatment of NAFLD.