Sugar substitute found in supermarkets can kill drug-resistant bacteria and help antibiotics work better

Saccharin, the artificial sweetener used in diet foods like yoghurts and sugar-free drinks, can kill multidrug-resistant bacteria – including one of the world’s most dangerous pathogens.

“Antibiotic resistance is one of the major threats to modern medicine,” said Professor Ronan McCarthy, who led the research at Brunel University of London’s  Antimicrobial Innovations Centre.

“Procedures such as tooth extractions and cancer treatment often rely on antibiotics to prevent or treat infection. But doctors are increasingly facing cases where the drugs no longer work.”

In 2019, antimicrobial resistance (AMR) killed 1.27 million people globally, with resistant infections contributing to nearly 5 million deaths.

Drug-resistant bacteria such as Acinetobacter baumannii, which causes life-threatening infections in people with a weakened immune system, and Pseudomonas aeruginosa, linked to chronic lung infections and sepsis, are on the World Health Organization’s list of top-priority pathogens.

“In exciting work led by our team, we’ve identified a novel antimicrobial – saccharin,” Prof McCarthy said. “Saccharin breaks the walls of bacterial pathogens, causing them to distort and eventually burst, killing the bacteria. Crucially, this damage lets antibiotics slip inside, overwhelming their resistance systems.”

Saccharin has been part of the human diet for longer than 100 years. While it has been extensively tested for safety in people, little was known about its effect on bacteria – until now with this study in EMBO Molecular Medicine.

The international team found that saccharin both stops bacterial growth and disrupts DNA replication and stops the bacteria from forming biofilms – sticky, protective layers that help them survive antibiotics.

They also created a saccharin-loaded hydrogel wound dressing  that, in tests, outperformed market-leading silver-based antimicrobial dressings currently used in hospitals.

“This is very exciting,” Prof McCarthy added. “Normally it takes billions of dollars and decades to develop a new antibiotic. But here we have a compound that’s already widely used, and it not only kills drug-resistant bacteria but also makes existing antibiotics more effective.

“Artificial sweeteners are found in many diet and sugar-free foods. We discovered that the same sweeteners you have with your coffee or in a ‘sugar-free’ drink could make some of the world’s most dangerous bacteria easier to treat.”

The World Health Organization has warned that the world is heading toward a ‘post-antibiotic era’, where common everyday infections could once again become deadly. Overuse of antibiotics in medicine and agriculture has accelerated resistance, and new antibiotics have been slow to arrive.

“This has created a dangerous situation,” said Prof McCarthy. “We urgently need new drugs to treat resistant infections – and saccharin could represent a new therapeutic approach with exciting promise.”