Revenge is sweet: Experts hope the toxin found in sugarcane will turn the tide against drug-resistant superbugs – calling it the ‘most promising antibiotic in decades’.
- Albicidin is an antibiotic made by pathogens in sugar cane leaves
- Scientists have discovered that the molecule blocks infection by changing its shape
- Recent tests have shown it to be effective against salmonella, E. coli and pneumonia
A toxin found in sugar that wipes out superbugs has been called the “most exciting antibiotic candidate” in decades.
Albicidin is a toxin produced by the plant pathogen that causes the devastating cane leaf smut disease. Researchers found that albicidin was effective against six antibiotic-resistant bacteria in a new laboratory study.
Scientists hope it will give them a new weapon to fight superbugs, which are estimated to contribute to about seven million deaths a year. Experts have warned they should be taken as seriously as global warming.
The antibiotic — called albicidin — is made by the plant pathogen that causes the devastating cane leaf smut disease, a bacterial disease that can ruin crops
dr Dmitry Ghilarov, head of the research group studying albicidin at the John Innes Center in Norwich, UK, said: “We think this is one of the most exciting new antibiotic candidates in many years.
“It has extremely high potency at small concentrations and is highly effective against pathogenic bacteria – even those resistant to the widely used antibiotics.”
Albicidin is used by the pathogen Xanthomonas albilineans to spread throughout the plant, withering the leaves and rendering the crop unusable.
The development of albicidin as an antibiotic was slow because scientists couldn’t figure out exactly how it interacts with its target in plants – the bacterial enzyme DNA gyrase.
Albicidin prevents a process that allows cells to function properly.
Gyrase, a bacterial enzyme, binds to DNA and twists it into a spiral in a process called supercoiling, which is crucial for cells to function.
During supercoiling, the DNA is temporarily broken.
Albicidin prevents the reunion of DNA by changing shape and effectively blocking the pathway.
Now scientists have this additional structural understanding of how albicidin works and hope to use it to modify the antibiotic and make it more effective against drug-resistant bacteria.
In the latest study, scientists used a powerful microscope to discover that albicidin adopts an L-shape, preventing the gyrase from rejoining the broken DNA, like “a wrench thrown between two gears”.
The way albicidin interacts is sufficiently different from existing antibiotics, which are likely to work against many of the current antibiotic-resistant bacteria.
Through laboratory testing, the scientists found that it was effective against some of the most dangerous bacterial infections commonly seen in hospitals, including salmonella, E. coli and pneumonia.
It’s estimated that these three antibiotic-resistant bugs kill more than 50,000 Americans each year.
When antibiotics are taken unnecessarily, bacteria can develop the ability to defeat them and gradually become drug-resistant.
dr Ghilarov said: “Albicidin seems to target a really essential part of the enzyme because of the nature of the interaction and it is difficult for bacteria to develop resistance to it.
“Now that we have a structural understanding, we can try to further exploit this binding pocket and make further modifications to albicidin to improve its potency and pharmacological properties.”
Now the researchers will seek funding for human clinical trials that they hope will lead to the creation of a new class of antibiotics.
The results were published in the journal Nature Catalysis.
Figures estimate that superbugs will kill 10 million people each year by 2050, with patients succumbing to the once harmless bugs.
Around 700,000 people worldwide die each year from drug-resistant infections, including tuberculosis (TB), HIV and malaria.
Again and again it was feared that medicine would be taken back to the “dark ages” when antibiotics would become ineffective in the years to come.
Aside from existing drugs becoming less effective, only one or two new antibiotics have been developed in the last 30 years.
In 2019, the WHO warned that antibiotics were “running out” when a report found a “serious shortage” of new drugs in the development pipeline.
Without antibiotics, caesarean sections, cancer treatments and hip replacements would be incredibly “risky”, it was said at the time.