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Scientists studying infections used to focus mainly on the direct interaction of the immune system with pathogens, but have since moved on to look more closely at the interactions that go on between microbiota, immune system and pathogen. Using mouse models, researchers from the Helmholtz Centre for Infection Research (HZI) recently elucidated a relationship between gut microbiomes of various compositions and the susceptibility to Salmonella infections. In their study, the scientists from Braunschweig identified several bacterial families that have a protective effect against Salmonella. The researchers also elucidated the immune mechanism in the mucosa of the gut that is regulated by the protective bacterial families. Published in Cell Host & Microbe, the results of the study of the HZI scientists are an important step towards a better understanding of the interactions of the triad of microbiota, immune system and pathogen.

Intestinal bacteria are suspected of causing cardiovascular disease, since they produce trimethylamine as a metabolic product that is hazardous to humans. They utilise food ingredients that are present mainly in meat and eggs. The causal relationships are still vague at this time, since important insights into these microbial communities are still lacking. A research team from the Helmholtz Centre for Infection Research (HZI) recently developed a special function-based diagnostic method that allows the measurement of the trimethylamine production potential of intestinal communities and identification of the specific bacterial species involved in this process. Based on these insights, the microbiome may become a target of therapeutics in the distant future. The researchers published the results in Microbiome.

In recent years, more and more pathogens have become resistant to previously time-proven antibiotics. This scenario gives scientists all over the world cause to find new anti-infective substances and to develop them for application in medicine. A true opportunity for the discovery of new antibiotics is the investigation of previously unknown bacteria and fungi from habitats that have not yet been examined thoroughly, as these microorganisms produce a wealth of chemical substances with antibiotic activity. Scientists from the Helmholtz Centre for Infection Research (HZI) have isolated a large number of new bacterial strains, some of which show an activity against resistant pathogens and have already been promoted to the early preclinical development phase.

Cells inside the human body contain a flexible polymer network called the cytoskeleton which consists of actin filaments - and other components - and undergoes constant assembly and disassembly. This turnover of actin filaments allows cells to change shape and move. Such movements are important for example during embryonic development, wound healing but also for a properly operating immune system. To be able to move through tissue, cells need to expend energy and apply force. For example, immune cells advance into all regions of our body to detect and fight pathogens. In turn, though, some pathogens can abuse the cytoskeleton to adhere to or penetrate into cells.

Many bacteria move by rotating long, thin filaments called flagella. Flagella are made of several tens of thousands building blocks outside the bacterial cell and grow up to ten times longer than the bacterial cell body. They allow bacteria to swim towards a nutrient source or to approach cells of the human mucosa in order to infect them. This means that flagella are also tools in infection processes and might be suitable as potential targets for new agents against pathogenic bacteria. The details of how flagella are assembled and how this process might be inhibited remained elusive. Scientists of the Helmholtz Centre for Infection Research (HZI) in Braunschweig now elucidated this mechanism using real-time observations of growing flagella. The researchers published their results in the freely accessible journal, eLife.

There is a continuing need for effective vaccinations against viruses which specifically infect the liver. According to the World Health Organization WHO, approximately 400 million people around the world are infected by hepatitis B or hepatitis C viruses and approximately 1.4 million people succumb to them each year. Moreover, chronic hepatitis B or C infections are amongst the most common causes of liver cancer and therefore are some of the most common reasons for a liver transplantation. Recently, a research team directed by Prof Dunja Bruder, who holds appointments at both the Helmholtz Centre for Infection Research (HZI) and the Otto von Guericke University Magdeburg, successfully targeted a vaccine specifically to recognition molecules of certain immune cells which allowed them to elicit an effective immune defence in the liver. The researchers published their results in Scientific Reports.