Researchers have discovered foodborne bacteria, or gut pathogens, in the gastrointestinal track make people sick because they thrive on the very same immune system responses initiated by the body to repair the damage the bacteria cause.
A large intestine at the peak of health is generally oxygen-free, offering an anaerobic environment for beneficial gut bacteria to thrive in. Gut pathogens, on the other hand, like Escherichia coli (E. coli), require oxygen to survive, so they work to change the environment in the gut to create ideal conditions for their growth.
To achieve this, gut pathogens damage the lining of the intestines, deploying virulence factors that lead to diarrhea. The body senses the disturbance and sets to work accelerating epithelial cell division on the intestinal lining. This cell renewal process brings up immature cells to the surface, which contain a lot of oxygen. And because these new cells have a lot of oxygen, they end up increasing the large intestine's oxygen levels, which gut pathogens love.
According to Andreas Bäumler, lead author of the study published in the journal Science, their findings are important because it shows how enteric pathogens are able to manipulate cells to acquire the oxygen they need to survive. At the same time, the results of their study offer a new insight into how strategies can be developed to target intestinal lining metabolism in an effort to prevent pathogens from taking up shop in the gut.
Unfortunately, controlling gut pathogens has become more problematic with antibiotic overuse.
"As more bacterial strains do not respond to the drugs designed to kill them, the advances made in treating infectious diseases over the last 50 years are in jeopardy," explained Bäumler.
In 2016, the U.S. Centers for Disease Control and Prevention identified three drug-resistant bacteria requiring immediate attention: Carbapenem enterobacteriaceae, Neisseria gonorrhoeae and Clostridium difficile.
A UK report also predicted that antibiotic-resistant bacterial infections will be claiming 10 million lives every year and costing the global economy $100 trillion to address by 2050 if they are not addressed.
As a result, more and more researchers are studying how gut pathogens affect the whole body. Antibiotic resistance is the major focus of research, but studies are also in place to determine how imbalances in gut bacteria affects a number of conditions beyond the gastrointestinal tract, like cardiovascular disease, brain health, asthma, arthritis and autism.
Recently, researchers from the Harvard Medical School and the Technion-Israel Institute of Technology carried out an experiment to show how E. coli bacteria evolves and grows as it develops antibiotic resistance.
Photo: James Palinsad | Flickr