By taking their energy sources, "good" Gut microbes keep pathogens at bay

By taking their energy sources, "good" Gut microbes keep pathogens at bay ...

New study from UC Davis Health reveals that bacteria in the gut probiotics might aid in eliminating bacteria that may be called Salmonella by competing with them for new funding.

The study, published today inCell Host & Microbe, demonstrates that alone the availability of required minerals does not define where bacteria including pathogens like Salmonella can survive and thrive in the gut.

Selon Mmegan Liou, an MD candidate for theBaumler Labat UC Davis and the first author of the study, these insights help develop better intestinal colonization strategies.

Humans are limited to using oxygen the air we breathe to generate energy. Microbes have developed energy therapies that can breathe different compounds and elements, such as nitrates. These mechanisms allow microbes to survive in many different situations.

Among the participants in this study, researchers identified a friendly strain of bacteria,Escherichia colistrain Nissle 1917 (E. coli) andSalmonella, a potentially harmful strain of bacteria that can cause gastrointestinal problems in humans and animals. (Some strains ofE. Colican may cause illness, but most are harmful.)

Microbes use nitrate for energy

Nitrate is well-known as a food preservative, but it is also a valuable resourcefor gut microbes. Nitrate is also available in the gut as an result of everyday metabolic processes. It is generally at very low levels but increases during inflammation.

Both bacteria strains in the gut use nitrate for energy. However, researchers found that Salamonellacan only use nitrate generated byphagocytes, a specific type of immune cells the body sends to repair injured or infected tissues.

TheE. coliuses nitrate is produced by both gut cells epithelial tissue and phagocytes, allowing it to compete with theSalmonella for its energy source.

Liou compares these different sources of nitrates to different restaurants in which the microbes can acquire the resources they need to grow.

According to Liou, the ability of E. coliNissle to dine at phagocytes and compete with the pathogen for resources was critical for the probiotic to confer protection againstSalmonella.

When the researchers infected mice withSalmonella, the inflammation in the gut was expected, resulting in immune cells phagocytes being brought into the intestinal lumen, the layer that lines the intestines.Salmonella was able to find a niche in the intestines rich in phagocytes, and exclusively used the nitrates created by these immune cells.

WhereSalmonellacan has the potential to obtain resources, sensors are too limited.

TheSalmonelladid not use the nitrate obtained by the immune-response tissue, limiting the number of people it might dine? One disturbing aspect of the competition between the probioticE. coli and the disease-inducingSalmonella was why theSalmonella did not use the healthy gut tissue''s nitrate. Why did it only use the nitrate produced by the immune-response tissue, causing it to lose control of the number

The researchers looked at the answer in sensors ofSalmonella, which allow bacteria to explore its surroundings and proceed toward a more pleasant environment, known as chemotaxis receptors. They steered the pathogen away from the epithelial-derived nitrate and toward the inflammatory phagocyte cells.

TheSalmonelladid not have a sensing mechanism that would steer it towards the healthy epithelial tissue, even if that tissue also created nitrates. The probioticE. colilacks has its chemotaxis receptors, which allow it to occupy both niches and compete against the pathogen in the latter''s preferred environment.

Our research identifies the properties of probiotics that protect us from infection, according toAndreas Baumler, the senior author of the study. Baumler is a vice-chair of research and a professor in the Department of Medical Microbiology and Immunology at the University of California. These insights provide a better understanding of intestinal colonization''s nutritional basis and can assist in development efforts to combat infection.

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