Fight infections with beneficial intestinal bacteria.


According to a recent announcement, an international research team led by David Berry from the Center for Microbiology and Environmental Systems Sciences at the University of Vienna has investigated whether natural intestinal flora can be used to prevent gastrointestinal infections (Clostridioides difficile) after antibiotic treatment. The microbiologists found that intestinal bacteria can attenuate the infection. The results were published in the journal “Nature Communications”.

Although antibiotics are vital drugs in the fight against various bacterially induced infectious diseases, treatment with such drugs is usually accompanied by undesirable side effects. For example, gastrointestinal infections are frequent. Researchers have now investigated whether such infections can be prevented with the help of the natural intestinal flora.

Antibiotics can be used to effectively treat bacterially caused infectious diseases. In general, the drugs are well tolerated, but undesirable side effects can also occur. For example, gastrointestinal infections often occur after antibiotic treatment because the natural intestinal flora, which is also intact and provides protection against pathogens, is disturbed. A possible strategy to prevent such infections is the administration of useful intestinal microbes as probiotics. Here, however, targeted research is needed to understand the underlying mechanisms. Only this will make it possible to develop probiotics that are tailored to the infection.

The human body is densely populated with microbes, the majority of which live in the gastrointestinal tract where they form the so-called intestinal flora. This plays an important role in human health. The beneficial microorganisms that are usually found in a healthy intestine, called “commensal” microorganisms, can protect us from infections caused by harmful microbes, i.e. pathogens, among other things. Because a healthy intestinal flora directly competes with pathogens for the energy resources in the intestine, it can prevent the growth of harmful microbes.

Side effects of antibiotic treatments

However, some drugs, such as antibiotics or immunosuppressants, can also interfere with or even kill commensal microbes as a side effect. In this case, there can then be a proliferation of pathogens, resulting in infections or diseases. According to the report, the bacterium Clostridioides difficile is the main trigger of gastrointestinal infections after antibiotic treatment in industrialized countries. Researchers are therefore looking for commensal microorganisms that prevent the growth of C. difficile in the intestine from the outset.

In order to understand which commensal intestinal microbes play a key role in this process, a team of researchers from the Center for Microbiology and Environmental Systems Sciences and the Faculty of Chemistry at the University of Vienna, the ETH Zurich and the Helmholtz Center for Environmental Research UFZ, led by David Berry, has identified commensal microbes that feed on the same sugars in the intestinal mucosa that serve as an energy source for C. difficile.

To determine the microorganisms, the scientists used heavy water, which is absorbed by the microbes together with the sugars under investigation. Organisms labeled in this way were then sorted out and examined using so-called Raman microspectroscopy in combination with cell sorting by optofluidics and high-resolution mass spectrometry. Using this methodology, the research team was able to identify a total of 51 different commensal microorganisms that process the same sugars of the intestinal mucosa as Clostridioides difficile.

Fighting infections with intestinal bacteria

Subsequently, the researchers used tests on mice to investigate whether a mix of five of these identified commensal microorganisms could prevent infection by C. difficile. It turned out that the addition of the identified microbes could not completely prevent infection with C. difficile, but could attenuate it. “C. difficile can probably also obtain energy from alternative sources and thus establish itself in the intestine. The key to finally prevent infection potentially lies in a more complex mixture of commensal intestinal microbes. A mixture containing additional organisms that compete with C. difficile for these alternative energy sources. Further research is needed to clarify this,” explains first author Fatima Pereira from the Center for Microbiology and Environmental Systems Sciences. (ad)

WashingtonNewsday Health and Wellness.


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