The microbiome has been investigated in relation to IBDs for decades, and now we know that bacteria have a role: in most research models the disease does not appear in the absence of microorganisms.

In humans, deep microbial genotyping has clearly shown that an altered diversity is observed when comparing patients with IBD or ulcerative colitis or Crohn’s disease with healthy controls.

There is therefore a reduced diversity both in ulcerative colitis and in Crohn’s disease, but one point is not clear yet: is the change in diversity a cause or an effect of the inflammation that develops in patients? Although some studies have shown that even at the time of diagnosis the microbiota has already undergone variations, the question is not yet answered.

Despite this, in a number of basic and translational studies researchers are trying to manipulate the microbiota for therapeutic purposes and some companies are aiming to develop new therapies based on these bacteria.

A prospect is certainly faecal transplantation, which is effective mainly in C. difficile infections and could also work for chronic inflammatory bowel diseases. It is unknown if it will be effective: in fact, intestinal microbiota transplants transfer a great diversity of organisms: not only “the good ones”, but also the “bad ones”. However, the results coming from the scientific literature are promising, particularly in the treatment of ulcerative colitis.

Studies are still ongoing and, as explained by Scott Snapper, gastroenterologist, professor at Harvard Medical School and director of the Inflamatory Bowel Disease Center at Boston Children’s Hospital, Massachusetts, it is not yet possible to give a definitive judgment.