Oxygen can ‘wake up’ dormant bacteria to weaponise as antibiotics

9 Dec 2016

Antibodies illustration. Image: urfin/Shutterstock

New research into finding possible answers to a post-antibiotic future has come across the use of oxygen as a means of ‘waking up’ dormant bacteria cells, with the aim of weaponising it to become antibiotics.

The possibility of a post-antibiotic era – whereby even the most common of infections would become untreatable – is being presented less and less as a case of if, but when.

With cases of antibiotic resistance appearing across the world – even against the ‘last resort’ antibiotic of colistin – researchers are now rushing to find possible new antibiotics or other effective forms of treatment.

Now the latest effort is being undertaken by a team of US and Spanish researchers who plan on using one of the most abundant elements on our planet – oxygen – to weaponise dormant bacteria in biofilms.

One of the problems found with treatments using antibiotics is that they are only effective against bacteria that are actively growing and dividing.

But when the body undergoes environmental stress, the bacterial mechanism that creates a toxin makes the cell dormant and therefore, antibiotic resistant.

One such bacterium is found in the gastrointestinal track where bile secreted by the liver results in it becoming dormant.

However, when the bile is gone, the inhibitor protein is destroyed – making the bacteria come alive again, known as a toxin antitoxin system.

Antibiotic resistance

Oxygen binding with bacteria. Image: Miquel Pons, University of Barcelona

Making better antimicrobials

Analysing the process, this toxin antitoxin system is the first known one to be oxygen-dependent. The E coli antitoxin’s structure has channels that are just large enough for oxygen to pass through.

Unlike other toxin antitoxin pairs, where the toxin makes the cell dormant and the antitoxin inactivates the toxin by binding, this system needs oxygen in the presence of the antitoxin to oxidise the toxin and ‘wake up’ the bacteria.

In research now published in Nature Communications, the team found that an increase of oxygen by 10pc was enough to wake up the bacteria.

“If we understand the toxin antitoxin systems at a molecular or atomic level, we can make better antimicrobials,” said Prof Thomas Wood from Penn State University, who was involved in the project.

“I would argue that the toxin antitoxin systems are fundamental to the physiology of all bacteria. We hope this will give us insight into how they survive the antibiotics.”

Colm Gorey was a senior journalist with Silicon Republic