Probiotics and antibiotics in IBD.

The involvement of the gut microbiota in the pathogenesis of IBD is supported by many findings and is thus now commonly acknowledged. The imbalance in the composition of the microbiota (dysbiosis) observed in IBD patients is one of the strongest arguments and provides the rationale for a therapeutic manipulation of the gut microbiota. The tools available to achieve this goal include fecal microbiota transplantation, but antibiotics and probiotics have been the most used one until now. Although antibiotics have shown some efficacy in inducing remission in Crohn's disease (CD) and ulcerative colitis (UC), as well as preventing postoperative relapse in CD, they are not currently recommended for the treatment of IBD except for septic complications, notably because of long-term tolerance and ecological issues. Some probiotics have been shown to be as good as 5-aminosalicylic acid to maintain remission in mild-to-moderate UC, but have been disappointing until now in CD in all tested indications. In pouchitis, antibiotics and probiotics have shown efficacy for inducing and maintaining remission, respectively. Targeting the gut microbiota in IBD is an attractive strategy. Current efforts to better understand the host-microbiota interactions in physiological as well as disease settings might lead to the development of rational-based treatments.