Antibiotics At The Origin Of Intestinal Inflammation

In the lives of scientists, many times lucky coincidences occur that make their occupation exciting. As happened to Dr. Koji Atarashi, from Keio University in Tokyo (Japan), when he discovered the very possible relationship between bacteria in the mouth and inflammatory bowel diseases.

The finding occurred when significant amounts of oral bacteria were found in stool samples from patients with ulcerative colitis and Crohn’s disease. Upon discovering this fact, they obtained samples of bacteria from patients suffering from intestinal inflammation and inoculated them into mice; the results, published in the journal Science , were surprising.

Antibiotic-resistant bacteria in the mouth cause inflammation

In the first experiment, the researchers took saliva from patients with ulcerative colitis and Crohn’s disease and inoculated it into mice with intestines cleared of any germs. Some mice developed intestinal inflammation, comparable to intestinal disorders in humans.

Taking a closer look, they found that a bacterium, Klebsiella pneumoniae, played an important role in the inflammatory reaction. These bacteria usually live in the mouth and reach the intestine with the liter and a half of saliva that we swallow daily.

However, when the microbiota is healthy, they do not colonize the intestine – although there may be a small reservoir – and they are not found in the feces.

Microbiota altered by antibiotics

The research got even more interesting when the researchers inoculated the bacteria directly into the guts of healthy mice that had not received any prior treatment. These types of mice did not show any symptoms of inflammation. However, if they were treated with antibiotics, then inflammation appeared in the intestines of the animals.

This demonstrated very clearly that Klebsiellas can proliferate after antibiotic treatment and thereby establish the basis for inflammatory bowel disease. And is that the Klebsiellas can be very resistant to a large number of antibiotics.

Other studies have confirmed that people with inflammatory bowel diseases have more Klebsiellas in their intestines than healthy people, and also that their condition worsens after antibiotic treatments.

Pathogenic bacteria replace beneficial ones

According to the researchers, Klebsiellas strains from saliva activate TH1 lymphocytes in the intestine, which are associated with the inflammation that accompanies the immune response. As the researchers noted, “Antibiotic-resistant Klebsiellas can gradually replace part of the microbiota in genetically predisposed patients, leading to significant inflammation in the gut.”

Also, in people with suppressed immunity, these bacteria can cause life-threatening urinary tract, lung, and blood infections .

The authors believe that a treatment that controlled the proliferation of these oral bacteria could be an effective therapeutic strategy to treat inflammatory bowel disease and many other disorders.

Specifically, they propose to identify and promote the growth of beneficial bacteria of the intestinal microbiota that can offer resistance to the development of Klebsiellas.