• Inflammatory bowel disease
• cell culture
• lactococcus
• probiotics
• cellular immunology
• Crohn's disease
• dendritic cells
• colonic adenomas
• hedgehog signalling
• colon carcinogenesis
• signal transduction

Important advances are being made in our understanding of the composition and function of the large amount of commensal bacteria that the human intestine has long been known to contain. Metagenomic sequencing has shown that the microbiome of healthy individuals is different from that of patients with inflammatory bowel disease (IBD) and that the microbial composition of patients with Crohn's disease is distinct from ulcerative colitis.1 Whether such microbial alterations in patients with IBD are the cause or consequence of the disease remains to be determined.

Attempts to modulate intestinal disease with bacteria started with the treatment of acute gastrointestinal infections by Alfred Nissle with a strain of Escherichia coli in 1917. Bacterial treatments have been attempted for a large variety of indications, mainly with different Lactococcal and Bifidobacterial species. In general, the better designed trials have shown modest if any clinical effects for most diseases in humans, with the exception of some indications in ulcerative colitis and pouchitis.2 Perhaps the emerging insight into the composition of our microbiota in health and disease will lead to more rational bacterial modulation and open up truly new therapeutic avenues. The development of such disease-modifying microbiotic treatments for …