Microbial pathogens find their way into our bodies in different of ways. Two important routes of transmission include food and drinking water. If a food-borne pathogen triggers an epidemic, the starting point of the chain of infection must quickly be identified to effectively curtail the epidemic. Now, HZI scientists have found a way to trace the routes of infection of bacterial pathogens that are present in our food and drinking water. Using high-resolution methods, the researchers are able to readily identify individual pathogenic bacterial strains.
Legionella are waiting for us everywhere warm freshwater is stored – inside water pipes, air conditioners, or swimming pools. Inhaling these bacteria along with the water vapor can sometimes be enough to cause severe pneumonia. Accurately identifying legionella can be tricky: they grow only poorly on traditional culture medium and frequently enter into a “viable but nonculturable“ state.
The marine bacterium Vibrio parahaemolyticus, which can end up on our tables in contaminated or undercooked mussles, presents a very similar problem. This bacterium can trigger cholera-like diarrheal infections and frequently causes diarrheal epidemics in the entire Pacific range, in the US, and, in recent times, even in Europe.
In order to track down these types of pathogens – and identify the source of the infection – HZI scientists have come up with a technology that is based on genetic marker sequences, which exist repeatedly and variably in the genome. These markers are unique for every single bacterial strain – even within the same species. The method, called “multi-loci variable number of tandem repeat analytic“ (or MLVA for short), yields a unique fingerprint of each bacterial strain. Using MLVA, our scientists are able to not only identify individual bacterial strains but also track their evolution into new strains.
One process, many faces. In the case of the marine pathogen, for example, it is very important to be able to trace its evolution and thereby understand its infectiosity.
The real challenge in trying to detect the presence of legionella is akin to trying to find a needle in a haystack – essentially, you are looking to locate a few bacterial cells in a massive body of water. Simply detecting the presence of this bacterium inside an air conditioner’s cooling unit or in our drinking water supply does not by itself represent a threat to our health – because not every strain of legionella automatically causes pneumonia. Our HZI scientists have even developed a method for directly studying tap water – without having to first culture the bacteria.
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- Legionärskrankheit – Wissenschaftler auf Spurensuche in der Wasserleitung
Legionellen warten überall auf uns wo warmes Wasser gespeichert wird – in Wasserleitungen, Klimaanlagen, Schwimmbädern. Einige wenige dieser Bakterien können schon ausreichen, um bei uns eine schwere Lungenentzündung zu verursachen. Häufen sich Fälle – etwa in einem Einkaufszentrum oder einem Schwimmbad – gehen Wissenschaftler auf Legionellensuche. Manfred Höfle hat eine Technologie entwickelt, mit der er genau die Legionellen findet, die die Menschen krank machen. Begleiten Sie ihn bei seiner Detektivarbeit...