Discovery of two new bacterial species in patients with inflammatory bowel disease

The discovery could help find new treatments in the future

Researchers from UMC Utrecht and Yale University have discovered two new bacterial species in patients with inflammatory bowel disease. These new species break down the protective mucous layer of the intestinal wall, causing violent immune reactions. This discovery could help find new treatments in the future.

The intestinal tract contains thousands of bacterial species, many of which have never been cultured and studied in the laboratory. Using cutting-edge culturomics, researchers were able to isolate two new bacterial species from the intestinal tract of patients with IBD, a chronic inflammatory disease that primarily involves the Crohn’s disease and ulcerative colitis, which affects millions of people around the world. It’s still unclear what causes IBD, but doctors have long believed that a strong immune response against the gut microbiota plays a major role in it. “Although these are preliminary results, it is tempting to assume that the new bacterial species, or other species with similar characteristics, play a role in the intestinal inflammation seen in patients with IBD,” said lead researcher Marcel de Zoete of UMC Utrecht. .

Pathogenic bacteria for animals and humans
Now that researchers from UMC Utrecht and Yale University (USA) have isolated the new bacteria, which have been given the names Allobaculum mucilyticum and Allobaculum fili, from the intestines of patients with IBD, they can continue their research. For example, their extensive DNA analysis has already shown that the new species are distant cousins ​​of Erysipelothrix rhusiopathiae, a pathogenic bacterium that infects various animal species such as pigs, turkeys and chickens, but also occasionally humans. .

Decomposition of the intestinal mucus layer
In two complementary studies, the researchers then looked at the characteristics of Allobaculum mucilyticum and the role that this bacterium could play in intestinal diseases. The bacterium has proven to be a very effective degrader of intestinal mucus, the protective slime layer that forms a barrier between (most) intestinal bacteria and the intestinal wall. Using a combination of genetic, proteomic and biochemical analyses, they were able to demonstrate that Allobaculum mucilyticum releases various enzymes during growth that break down sugars from the intestinal mucus. These released sugars can then be used to further support bacterial growth, but can also reduce the protective function of the gut lining.

New perspectives for the future
Finally, with the team of Dr. Noah Palm from Yale University, Allobaculum mucilyticum has been shown to cause intestinal inflammation in infected mice and disrupt the immune response to a common human commensal bacterium. Marcel: “There is still a long way to go before we fully understand the role of the gut microbiota in the pathological process of IBD, but studies like this are important steps that can provide new insights and directions for future treatment. preventive.