Number of the Month: 200 nanometres

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The news caused many people around the world to shudder: in early 2017, a woman in the United States died from an infection after all 26 US-approved antibiotics had no effect. Scientists have long been extremely concerned about such pathogens that cannot be combated by any antibiotic. They are also known as multi-drug resistant bacteria. The World Health Organization (WHO) and many epidemic research institutions see them as one of the biggest threats to health. They cause some 700,000 deaths around the world each year.

How serious infections can be combated by a virus

bacteriophages are tiny, but can do great things

But what can be done if antibiotics no longer have any effect on serious infections such as hospital germs, septicaemia or pneumonia? Researchers have particularly high hopes for what are known as bacteriophages, or phages for short. At a mere 200 nanometres long, these are tiny viruses that can be seen only under a microscope. They look a bit like small Mars robots. They have a head that contains their genetic material, and a long neck with little feet at the end. What they can do with these little feet is really something: they use them to position themselves on the surface of bacteria and inject their DNA into the host. This attacks the bacterium and destroys it – without causing any further damage to the human organism. Theoretically, phages can be used to treat infections against which antibiotics are no longer effective.

Searching for the right phages

However, one problem is that there are several different types of phages – each of which attacks only one specific bacterium. Furthermore, some produce toxins and are therefore not suitable for use in therapy. Consequently, researchers have to search for as many suitable phages as possible. At present, there is also a lack of any legal framework in the European Union to explicitly recognise their clinical application. Germany is committed to intensively researching phages and has made available a total of 15 million euros to fund the quest for new therapy forms. Since 2017, the Federal Ministry of Education and Research (BMBF) has been supporting industry and scientific associations in their efforts to find new drugs to fight bacteria. Research into phages is one area of focus.

Library of bacteria killers

The Leibniz Institute DSMZ – German Collection of Microorganisms and Cell Cultures in the North German city of Braunschweig is a particular expert in phage therapy. Scientists at the Microorganisms department there began building up a phage collection more than 25 years ago. In addition, they have launched a therapy phage database: a research group led by phage expert Dr Christine Rohde has created a kind of library of these bacteria killers in which they catalogue the diversity of the viruses and discover new phages.

Where bacteria and their enemies thrive

To this end, Dr Rohde and her colleagues often have to work in some pretty smelly environments: “The best place for us to look is in sewage systems, or in rivers and ponds, as well as in somewhat brackish water. You find what you are looking for often enough there.” This is because waste water treatment plants and hospital sewer systems are teeming with millions of bacteria – but also with their enemies, the bacteriophages. More than 500 different varieties are now stored in DSMZ’s highly secure basement.

An important source for the pharma industry

One of the organisations interested in this virus library is the Phage Technology Center (only in German) in the West German city of Bönen. By its own account, the company researches and produces “phage cocktails” for preventive use in areas such as animal feed, drinking water for animals, disinfectants and drugs in veterinary and human medicine. Although therapy involving phages is still somewhat problematic, the targeted support provided by the Federal Ministry of Education and Research could help drive forward new approaches more quickly. In which case, a cure for deadly bacteria might finally have been found again.