Festschrift for Ronan O'Connell: pouchitis, ulcerative colitis and the microbiome.

The hypothesis of altered bacterial communities contributing to the development of pouchitis began a scientific quest to link host mucosal factors, microbial metabolism and spatial structure of the colonic microbiome in ulcerative colitis, reaching its apotheosis with the integration of advanced spatial sampling with laser capture microdissection, mucin array profiling, molecular microbiology and next-generation sequencing technologies. This article, part of a festschrift, summarises the contributions of the O'Connell lab to the field of host-microbial interactions in inflammatory bowel disease.