How some resistant bacteria can even eat antibiotics as food

[Lance]

New scientist May 3 2018

 

SOME types of bacteria don't just resist antibiotics, they eat them too – and now we have worked out their trick.

Gautam Dantas at Washington University in St Louis, Missouri, and his colleagues discovered this by accident10 years ago. They were growing soil bacteria in the presence of penicillin, expecting that it would stop them from growing.

"But we saw exceptional growth on antibiotics," says Dantas. His team found that some strains were around 50 times above the threshold at which bacteria are normally classed as antibiotic-resistant, and that they were feeding on the penicillin.

Now, Dantas and his colleagues have figured out how these bacteria do it, by focusing on the genes that became active in four strains. Deleting these genes and observing the effects revealed that the bacteria are able to thrive on penicillin using a cocktail of enzymes: proteins that catalyse chemical reactions.

First, the bacteria use an enzyme to resist the antibiotic, so it doesn't stop them growing. Then they use a couple of enzymes to start breaking the penicillin apart, before deploying 10 or more enzymes that enable them to use the carbon in the degraded antibiotic as a food source. Giving genes for these enzymes to harmless E. coli bacteria enabled them to eat antibiotics the same way (Nature Chemical Biology, doi.org/cn23).

Antibiotics have been around for millions of years, so it is unsurprising that bacteria have evolved to use them as a food source, says Matthew Avison at the University of Bristol, UK.

Dantas hopes the findings will enable the creation of antibiotics that can't be broken down this way. The team's modified E. coli may also be useful as it could help deal with the antibiotics in sewage that later find their way into our tap water, says Jonathan Cox at Aston University, UK.

This article appeared in print under the headline "How some bacteria snack on antibiotics"

Jessica Hamzelou

[cricket246]

Wow! Isn't that like spitting in Jehovah's eyes and stealing 32 million dollars?! I would hate to be them in the end...