Purpose of review: Diverse research interests have converged on the gut microbiota because of its contribution to immune development, mucosal homeostasis and to the pathogenesis of a diversity of intestinal and extraintestinal disorders. Recent landmark findings are addressed here.
Recent findings: The impact of lifestyle, including dietary changes and antibiotics, on the microbiota has been mechanistically linked with disease risk. Microbial, immune and metabolic signalling are mutually interactive, with each of these being regulated by diet. Although changes in the microbiota have been found in several disorders and may have important therapeutic implications, some components of the commensal microbiota may behave like pathogens (pathobionts) depending on the context and host susceptibility.
Summary: Advances in understanding host-microbe interactions in the gut continue apace, they are relevant to a diversity of infectious, inflammatory, neoplastic and metabolic disorders and are poised for clinical translation.