“Antibiotic resistance is one of the major threats to modern medicine,” said Professor Ronan McCarthy of Brunel University London’s Antimicrobial Innovations Centre. His remarks highlight a crisis that killed 1.27 million people worldwide in 2019, and nearly 5 million have died from drug-resistant infections. In the midst of this dire scenario, an unexpected finding from one of the world’s most common diet foods has emerged: saccharin, the artificial sweetener that has found its way into countless sugar-free beverages and yogurts, has displayed potent antimicrobial activity against multidrug-resistant bugs.
Saccharin, a compound that has been part of the human diet for more than a century, is being studied as a possible weapon against pathogens such as Acinetobacter baumannii and Pseudomonas aeruginosa, both of which the World Health Organization has ranked as top-priority threats. These bacteria are best known for causing potentially life-threatening infections, especially in patients whose immune systems are suppressed by disease or treatment, and for resisting even last-line antibiotics. In a remarkable finding, McCarthy and his colleagues found that saccharin breaks through a protective glucose polymer coating on bacterial cell membranes that allows it to worm its way into a bacterial cell and disrupts cell wall integrity, causing cell wall distortion and lysis or rupture of the cell. This structural damage is fatal to the bacteria, but also gives antibiotics a chance to get in and bypass their resistance systems.
This discovery has far-reaching implications. The development of a new antibiotic usually costs billions of dollars and can take decades of research. But saccharin a compound that had already been widely consumed and extensively tested for human safety provides a shortcut to improving existing antibiotics. “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,” McCarthy said in an interview with Brunel University London.
The study also investigated saccharin’s potential to inhibit bacterial growth, interfere with DNA replication, and prevent biofilm formation. Biofilms sticky, protective layers that guard bacteria from antibiotics are a daunting hurdle in addressing chronic infections. Saccharin’s ability to break down these biofilms is a major step forward in the field of antimicrobial strategies. In addition, researchers created a saccharin-containing hydrogel wound dressing that showed better effectiveness than silver dysfunctional local antimicrobial dressing, which is extensively utilized in hospitals, confirming its ability in clinical applications.
Although saccharin has dominated the research field, saccharin is not alone in this respect, as other artificial sweeteners such as acesulfame-K (ace-K) and cyclamate display extensive multidrug-resistant pathogen inhibition. Ace-K was found to prevent bacterial virulence behaviors (biofilm formation, motility, and acquisition of antibiotic-resistant genes) in a study published in EMBO Molecular Medicine. The results suggested that the artificial sweeteners may be a kind of broad-spectrum antimicrobials tool with effects of broad spectrum towards Gram-negative and Gram-positive bacteria.
The workings of saccharin’s antimicrobial effects are also interesting. Saccharin destabilizes bacterial membranes and induces bulge-mediated lysis, thereby increasing permeability and causing cell death. This effect was seen in several bacterial species, including carbapenem-resistant E. coli that first filamented, bulged and lysed. These effects not only demonstrate how potent saccharin is but imply that saccharin has the potential to resensitize resistant bacteria to antibiotics. For example, saccharin profoundly lowered the minimum inhibitory concentrations of carbapenems important last-resort antibiotics against A. baumannii, a notorious superbug with incredible resistance abilities.
The discovery also raises concerns about how artificial sweeteners may affect gut bacteria on a larger scale. Some earlier studies have found that compounds such as sucralose can change the gut microbiome and interfere with bacterial signaling. Nevertheless, the capacity of saccharin and ace-K to repress virulence behaviors and increase the potency of antibiotics provides a new opportunity to repurpose these molecules in the clinic.
With the world inching closer to a “post-antibiotic era,” in which common infections could once again turn fatal, saccharin’s accidental antibacterial abilities provide a ray of hope. The World Health Organization has warned that the overuse of antibiotics in medicine and agriculture has sped resistance, and the pipeline for new antibiotics is alarmingly slow. Saccharin and other artificial sweeteners may offer a new therapeutic approach by repurposing compounds that are already widely used to address one of the thorniest challenges in global health.
The potential applications don’t stop with individual treatments. Antimicrobial releases such as saccharin from dressings and wound washes are effective in decontaminating biofilms, a leading cause of chronic wound infection. These results highlight the compound’s versatility, as well as its potential application in systemic and localized antimicrobial treatments.
This finding prompts a reconsideration of what artificial sweeteners are, not merely benign dietary additives but potential agents in curbing the rise of antibiotic resistance. “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.” It’ll take rigorous clinical trials and collaboration across disciplines to get there, but turning a nearly 100-year-old sweetener into a lifesaving antimicrobial agent stands testament to the power of scientific innovation.
