Investigating resistant bacteria in the gut

Enterobacteria are a specific class of bacteria that can cause infections in humans. For example, the enterobacterium Escherichia coli is the commonest cause of urinary tract and bloodstream infections. Usually, it is relatively easy to control these bacteria using antibiotics. In the last 30 years, however, there has been a dramatic increase in the number of multidrug-resistant bacteria – in other words, bacteria that are resistant to all kinds of antibiotics. It is estimated that antibiotic-resistant bacteria cause the deaths of 300 people each year, while the global figures is 1.3 million. This is why these pathogens are also known as superbugs.

Not every infection has a fatal outcome; many healthy people carry superbugs in their gut. Researchers around the world are currently developing strategies to eliminate these superbugs from the gut. Mouse models are usually used to assess the effectiveness of these strategies, a process that involves colonising mice with multidrug-resistant bacteria. Researchers then study what happens in the animals’ guts and how it might be possible to prevent infection.

As part of NRP 79, a research group led by Andrea Endimiani of the University of Bern will develop a new model that uses insect larvae instead of mice. The team will colonise the larvae with superbugs and then study how the bacteria react. "How does the gut flora, the microbiome, change? How long can the bacteria survive in the gut? What approaches can be used to kill the superbugs in the insect larvae? These are the questions we will be investigating," says Andrea Endimiani.

The first step is to build the model and analyse how it works. After that, the researchers will compare the conventional mouse model with their new insect larvae model.

Using Zophobas morio larvae to design a new in vivo model of intestinal colonization due to multidrug-resistant Enterobacterales