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MRSA bacteria use "invisible sheath": the protein makes the pathogen invisible to the immune system



Effective camouflage: The researchers found out why our immune system often has no chance against the famous MRSA pathogens: many of these bacteria have a kind of invisible plaque. It is a protein that changes the surface of the bacteria so that they can no longer be recognized by the body's defense system. Interestingly, the MRSA bacteria acquired this useful protection from their enemies, as the team in the journal Nature reports.

MRSA bacteria are now resistant to numerous antibiotics - and are hiding with one

Meanwhile, MRSA bacteria are resistant to numerous antibiotics – and are hiding in front of our immune system with a "cloak of invisibility".

Staphylococcus aureus bacteria infections cause numerous deaths worldwide. Particularly dangerous are resistant strains of the pathogen called MRSA for short. These bacteria often appear in hospitals, but also are more common in normal households.

The problem: Especially immunocompromised people often fail to fight bacteria with their own defense mechanisms on their own body. They then become seriously ill – and the resistance of bacteria to the usual drugs complicates the treatment of such infections.

Changed surface

In order to develop more effective therapies for MRSA pathogens in the future, scientists are trying to better understand how these bacteria function. David Gerlach of the University of Typingen and his colleagues have now made an interesting discovery in this context: they found that bacteria can be made invisible to the immune system.

Many of the most common pathogens MRSA therefore have a kind of invisible gown. More precisely, this is a previously unknown protein on its surface, which it calls the TarP research team. "TarP changes the pattern of sugar molecules on the surface of the pathogen," explains colleague Gerlach Andreas Peshel. This leads to the fact that the immune system no longer recognizes the pathogen.

There are no antigens

As a result, its own defense system of the body can not produce antibodies to the most important MRSA antigen, diclonic acid. Thus he loses his most important weapon against the intruder. The effects of this loss were shown by experiments with human immune cells: they battled bacterial strains without TarP protein much more efficiently than those with this cloak of invisibility.

"The discovery of TarP has come as a complete surprise to us and very well explains why the immune system often has no chance against MRSA," co-author Tilo Shtel said. But how did bacteria gain this useful feature? Further research has shown that the camouflage cloak is the result of an argument between the pathogens and their natural enemies, the so-called. phages. Phases are viruses that attack bacteria and use them as host cells.

Work on the phases

In the case of Staphylococcus aureus, the phases apparently reprogrammed their host using the TarP protein and thus changed its surface, researchers said. "The discovery that phases can affect whether safe colonization inflicts on pathogenic infections can play a key role in the future of treating infections with MRSA," said non-microbiologists Michael Gilmore and She Miller Medical College Harvard in Boston.

The authors of the study see the following: "The results obtained will help us develop better therapies and vaccines against the pathogen," Stuyl said. In this way, it is possible to find active substances that block TarP and see the pathogen again for the immune system. (Nature, 2018, doi: 10.1038 / s41586-018-0730-x)


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