A general consensus exists that IBD is associated with compositional and metabolic changes in the intestinal microbiota (dysbiosis). However, a direct causal relationship between dysbiosis and IBD has not been definitively established in humans. Findings from animal models have revealed diverse and context-specific roles of the gut microbiota in health and disease, ranging from protective to pro-inflammatory actions. Moreover, evidence from these experimental models suggest that although gut bacteria often drive immune activation, chronic inflammation in turn shapes the gut microbiota and contributes to dysbiosis. The purpose of this Review is to summarize current associations between IBD and dysbiosis, describe the role of the gut microbiota in the context of specific animal models of colitis, and discuss the potential role of microbiota-focused interventions in the treatment of human IBD. Ultimately, more studies will be needed to define host–microbial relationships relevant to human disease and amenable to therapeutic interventions.

人们普遍认为IBD与肠道菌群的组成和代谢变化有关（营养不良）。然而，在人类中，铁血病和IBD之间没有直接的因果关系。动物模型的发现揭示了肠道菌群在健康和疾病中的多种作用和特定于上下文的作用，范围从保护作用到促炎作用。此外，来自这些实验模型的证据表明，尽管肠道细菌通常会驱动免疫激活，但慢性炎症反过来会影响肠道菌群并导致营养不良。这篇综述的目的是总结目前IBD与营养不良之间的关联，描述肠道菌群在特定的结肠炎动物模型中的作用，并讨论了以微生物群为中心的干预措施在治疗人IBD中的潜在作用。最终，将需要进行更多的研究来确定与人类疾病相关并适合治疗干预的宿主-微生物关系。