Science Update

E. coli proliferates in individuals with inflammatory bowel disease

Researchers at Penn State University identified a mechanism in which Escherichia coli proliferates in inflammatory bowel disease (IBD) during flare-ups.

Some strains of E. coli are normal healthy bacteria that compose part of the predominant flora in the gastrointestinal tract. In some patients with inflammatory bowel diseases researchers have found that the healthy E. coli may proliferate during a flare-up and further contribute to the patients symptoms and progression of the disease.

There are several types of inflammatory bowel diseases where opportunistic E. coli bacteria proliferates in the gut. IBD which primarily includes Crohns and ulcerative colitis involves chronic inflammation of all or part of the gastrointestinal tract.

Here is an example of this situation in one of my patients with Crohns disease.


The mechanisms by which this occurs with E. coli is not well understood. Identifying these mechanisms will help to reduce the E. coli burden on the inflamed gut and prevent chronic diseases often associated with IBD such as musculoskeletal and dermatological conditions.

Researchers studied the interactions between enterobactin myeloperoxidase and lipocalin 2 and how they regulate E. coli in the gastrointestinal tract. Enterobactin (Ent) is a chemical secreted by E. coli that takes iron from host proteins in the body and aids in the growth of E. coli. Myeloperoxidase (MPO) is an antibacterial protein that white blood cells produce to kill bacteria. However enterobactin inhibits myeloperoxidase from doing this.

Another protein produced by white blood cells Lipocalin 2 (Lcn2) collects the enterobactin so that the bacteria cannot obtain enough iron for their survival. The researchers found that Lcn2 can counteract the effects of Ent on MPO.

E. coli can be harmful under certain circumstances commonly seen in inflammatory bowel disease. This new study has defined a defense mechanism used by E. coli.

Bacteriophages can be a great option here. They are not very well known but are one of the most abundant naturally-occurring organisms on earth. They can be found everywhere from the soil to drinking water. They only prey on bacteria never human cells and the bacteria have a difficult time becoming resistant to them.  Phages are great because they are species specific meaning different strains attack different bacteria. This makes them harmless to human cells and even to non-targeted bacteria. This is much different than antibiotics that can wipe out all the beneficial bacteria of the gastrointestinal tract along with the harmful bacteria. Phages are classified as prebiotics and there are specific phages that can infect and inhibit the growth of E. coli only. Lytic phages are completely safe and considered GRAS (through review of published scientific literature and based on their common use in food).