Am J Gastroenterol. 2012 Nov;107(11):1752-4. doi: 10.1038/ajg.2012.291.
Humans harbor complex microbial communities that cover the skin and the mucosal surfaces, including the gastrointestinal mucosa. The intestinal microbiota has coevolved with humans and has a key role in immune and functional gut maturation, maintenance of homeostasis as well as regulation of functions beyond the gastrointestinal tract. On the other hand it is becoming apparent that compositional, metabolic, or genetic changes in this ecosystem (dysbiosis) are associated with disease. The development of high-throughput approaches to analyze the intestinal microbiota has increased markedly our knowledge of the intestinal microbiome. Although distinct associations between gut microbial communities and inflammatory bowel disease (IBD), irritable bowel syndrome (IBS), and celiac disease (CD) have been identified in adult individuals, no direct causal link to disease has been established. The relationship between dysbiosis and gastrointestinal diseases remains, thus far, circumstantial. This emphasizes the importance of studying the composition, diversity, and metabolic capacity of the intestinal microbiota in the context of mechanisms of disease and clinical phenotypes.
人类拥有复杂的微生物群落，覆盖皮肤和黏膜表面，包括胃肠道黏膜。肠道微生物群与人类共同进化，在免疫和肠道功能成熟、维持内稳态以及调节胃肠道以外的功能方面发挥着关键作用。另一方面，人们越来越清楚地认识到，这个生态系统（失调）在组成、代谢或遗传上的变化与疾病有关。高通量方法来分析肠道微生物群的发展显著增加了我们对肠道微生物组的认识。虽然在成年人中已经确定了肠道微生物群落与炎症性肠病（IBD）、肠易激综合征（IBS）和乳糜泻（CD）之间的明确关联，但尚未确定与疾病的直接因果关系。因此，肠道菌群失调与胃肠道疾病之间的关系仍然是间接的。这强调了在疾病机制和临床表型的背景下研究肠道微生物群的组成、多样性和代谢能力的重要性。
