Emerging concepts and shifting paradigms for understanding the microbial basis of inflammatory bowel diseases.

Inflammatory bowel diseases (IBDs) are complex immune disorders that arise at the intersection of genetic susceptibility, environmental exposures, and dysbiosis of the gut microbiota. Our understanding of the role of the microbiome in IBD has greatly expanded over the past few decades, although efforts to translate this knowledge into precision microbiome-based interventions for the prevention and management of disease have thus far met limited success. Here we survey and synthesize recent primary research in order to propose an updated conceptual framework for the role of the microbiome in IBD. We argue that accounting for gut microbiome context - elements such disease regionality, phase of disease, diet, medication use, and patient lifestyle - is essential for the development of a clear and mechanistic understanding of the microbiome's contribution to pathogenesis or health. Armed with better mechanistic and contextual understanding, we will be better prepared to translate this knowledge into effective and precise strategies for microbiome restitution.