An international team of researchers including scineitsts from The University of Tübingen, the German Center for Infection Research (DZIF) and The University of Manchester have achieved a breakthrough in the decoding of multi-resistant pathogens. The team led by Professor Andreas Peschel and Professor Thilo Stehle was able to decode the structure and function of a previously unknown protein used by dreaded pathogens such as Staphylococcus aureus like a magic cloak to protect themselves against the human immune system. The study was published in Nature

Dr Guoqing Xia and his PhD student Mr Wanchat Sirisarn, from the Division of infection, immunity and respiratory medicine, contributed to this study. Infections caused by bacteria such as Staphylococcus aureus cause many deaths worldwide. Staphylococcus aureus strains resistant to the antibiotic methicillin (MRSA for short) are particularly feared in hospitals. According to a study published at the beginning of November, there were around 670,000 diseases caused by multi-resistant pathogens in the EU alone in 2015 and 33,000 patients died.

Normally, our immune system copes well with pathogens such as bacteria or viruses. However, sometimes the defensive strategies of the human body fail, especially in immunocompromised patients. Most antibiotics are meanwhile ineffective against resistant pathogens. Effective replacement antibiotics and a protective vaccine against MRSA are not yet in sight. A precise understanding of the defence mechanisms could therefore lead to new therapies against the bacteria.

Researchers at the University of Tübingen have now described how MRSA bacteria become invisible to the immune system. They were able to show that many of the particularly frequent MRSA bacteria have acquired a previously unknown protein that prevents the pathogens from being detected by antibodies. The Tübingen scientists gave the protein the name TarP (short for teichoic acid ribitol P).

"TarP alters the pattern of carbohydrate molecules on the pathogen surface in a so far unknown way," explained Professor Andreas Peschel from the Interfaculty Institute of Microbiology and Infection Medicine at the University of Tübingen. "As a result, the immune system is unable to produce antibodies against the most important MRSA antigen, teichoic acid," said Peschel. “The immune system is ‘blinded’ and loses its most important weapon against the pathogen.”