New antibiotic found in soil has potential to fight superbugs

For nearly thirty years, the medical world has waited for a breakthrough in antibiotic development. As bacteria continue to evolve and outsmart existing drugs, antibiotic resistance has become one of the most pressing public health threats. The World Health Organization ranks antimicrobial resistance (AMR) among the top ten global health concerns.

Doctors now face infections they can no longer treat with available drugs. In hospitals, once-manageable conditions are turning fatal. This crisis has pushed scientists worldwide to search for new antibiotics – especially those that work differently from current ones.

Now, a team at McMaster University may have found what the world desperately needs: a brand-new molecule that can fight drug-resistant bacteria. Called lariocidin, this molecule could open a new chapter in the fight against superbugs.

New antibiotic candidate discovered

The discovery came from the lab of Professor Gerry Wright, an expert in biochemistry and biomedical sciences. His team, working at the Michael G. DeGroote Institute for Infectious Disease Research (IIDR), published their results in Nature on March 26, 2025.

The new antibiotic candidate, lariocidin, stands out not just for its power but also for its uniqueness. It belongs to a group of natural compounds called lasso peptides.

These molecules have a special knotted structure that helps them resist breakdown in harsh conditions. Lariocidin may be the first of its kind to block one of the most essential components in bacterial survival: the ribosome.

“Our old drugs are becoming less and less effective as bacteria become more and more resistant to them,” said Wright. “About 4.5 million people die every year due to antibiotic-resistant infections, and it’s only getting worse.”

That number speaks volumes. The team’s discovery could not come at a better time.

New antibiotic is a leap forward

Lasso peptides are known for their biological activity and their complex structures. They belong to a class called ribosomally synthesized and post-translationally modified peptides.

These molecules often interact with various bacterial targets, but until now, none had been shown to block the ribosome itself.

Lariocidin and its variant, lariocidin B, are produced by a strain of Paenibacillus bacteria found in backyard soil in Hamilton, Ontario. These molecules don’t just slow bacterial growth – they halt it by interfering with protein production. The ribosome, responsible for making proteins, becomes the primary target.

“This is a new molecule with a new mode of action,” Wright says. “It’s a big leap forward for us.”

A backyard discovery with global potential

To uncover lariocidin, the research team cultivated soil bacteria for nearly a year. This slow and steady approach allowed even sluggish microbial species to thrive. Among them was Paenibacillus sp. M2, quietly producing a substance with potent antibacterial properties.

“When we figured out how this new molecule kills other bacteria, it was a breakthrough moment,” says Manoj Jangra, a postdoctoral fellow in Wright’s lab.

Further analysis showed that lariocidin binds to a unique site on the small subunit of the bacterial ribosome. There, it interacts with 16S ribosomal RNA and aminoacyl-tRNA. This disrupts the ribosome’s normal function, preventing proper protein synthesis.

The result is twofold: blocked translocation and increased miscoding. Bacteria cannot survive this type of disruption.

A molecule built to beat resistance

One of lariocidin’s most exciting features is its ability to bypass resistance mechanisms. Many current antibiotics lose their power because bacteria adapt to destroy or eject them.

Lariocidin, however, avoids these common traps. Its structure and action are novel enough that bacteria haven’t yet developed a clear defense.

The molecule also shows a low chance of triggering spontaneous resistance. That makes it an excellent candidate for long-term clinical use. In early tests, lariocidin proved safe for human cells, showing no signs of toxicity.

In a mouse model of Acinetobacter baumannii infection – a notoriously resistant pathogen – the molecule performed impressively. Infections shrank, and the animals recovered better than expected.

A new path for antibiotic research

Despite its promise, lariocidin is not ready for hospital use just yet. Natural production by Paenibacillus is limited. The team must now modify the molecule and develop methods to produce it in larger quantities. This step is crucial for future testing and approval.

“The initial discovery – the big a-ha! moment – was astounding for us, but now the real hard work begins,” said Wright. “We’re now working on ripping this molecule apart and putting it back together again to make it a better drug candidate.”

That hard work involves genetic engineering, chemical tweaks, and scaling production. The road to clinical trials is long and full of hurdles. Still, the discovery of lariocidin offers a new direction – one grounded in both science and urgency.

Lariocidin is more than just a new compound; it introduces an entirely new chemical scaffold for antibiotics. Its unique action on the ribosome opens doors to future drugs built on the same model. For the first time in decades, scientists have a fresh template to explore.

As resistance continues to rise, discoveries like lariocidin offer hope. The fight against superbugs is far from over, but we may finally have a new weapon worth watching.

The study is published in the journal Nature.

—–

Like what you read? Subscribe to our newsletter for engaging articles, exclusive content, and the latest updates. 

Check us out on EarthSnap, a free app brought to you by Eric Ralls and Earth.com.

—–