Lyme borreliosis is the most common tick-borne infectious disease in Europe. Up to 70,000 new cases are estimated each year in Austria alone. The bacterial infection can cause lasting health problems for patients. A MedUni Vienna research team has made significant progress in understanding the mechanism of infection and identified a potential way forward for the development of targeted therapies that do not rely on antibiotics. The study was recently published in the „International Journal of Molecular Sciences“.

The scientific team led by Margarida Ruivo and Michiel Wijnveld from MedUni Vienna's Center for Pathophysiology, Infectiology and Immunology focused on the restriction-modification system (RMS) of Borrelia bacteria as part of the study. RMS refers to the protective mechanism of the Borrelia bacteria, which plays a decisive role in the defence against foreign genetic material (DNA) and can be described as a primitive immune system of these pathogens. "Our aim was to characterize the RMS of Borrelia afzelii and Borrelia garinii, the main pathogens of Lyme borreliosis in Europe, and to understand its importance for the survival of these bacteria during infection of the host," says study leader Michiel Wijnveld, explaining the background to the research work.

Targeted therapy as a possible alternative to antibiotics
In order to investigate the RMS in more detail, the researchers used an innovative method in which they modified and analyzed the DNA of Borrelia bacteria. They discovered that the methylation of DNA, a process in which small molecules are bound to the bacteria’s own DNA, plays an important role in protecting the bacteria against foreign DNA. Further experiments showed that the ability of bacteria to take up new genetic material stably can be significantly improved by pre-methylating DNA molecules to mimic the Borrelia’s own DNA. This provides a tool to investigate how borrelia sustains itself within a host such as a human and a possible, previously unknown approach for researching and developing new therapies against Lyme borreliosis that are not based on antibiotics. The researchers are considering phage therapy, in particular, as an alternative treatment method. This involves using so-called bacteriophages, i.e. viruses that attack bacteria, to combat the pathogens specifically. "With further research, this method has the potential to pave the way towards reducing our reliance on antibiotics and preventing the development of antibiotic resistance," says Wijnveld.

Lyme borreliosis is the most common tick-borne disease in Europe. Borrelia bacteria are transmitted to humans when infected ticks bite. Recent studies from the same research group at MedUni Vienna have shown that every fourth tick is carrying Borrelia in Austria. Treatment with antibiotics is best started as soon as possible after diagnosis of Lyme borreliosis. If the bacterial infection is not recognized in time, it can lead to serious complications such as heart and joint inflammation, neurological complications and persisting symptoms after treatment. There is currently no vaccination against Lyme borreliosis. Contrary to the still widespread opinion, a vaccination against TBE does not protect against Lyme borreliosis.