Molecule Discovered in Backyard Soil Can Fight Drug-Resistant Bacteria

A team of researchers from McMaster University has identified a new molecule – lariocidin – that can challenge some of the most drug-resistant bacteria on Earth. The discovery responds to a critical need for new antimicrobial medicines in the threatening era of antimicrobial resistance (AMR). The findings were published in Nature.

The AMR crisis

Sir Alexander Fleming’s landmark discovery of penicillin in 1928 led to the medical revolution of antibiotics, which have enabled doctors and surgeons to pursue new treatments that would have otherwise risked fatal infection. Today, antimicrobials are widely used not only in human healthcare but also in household cleaning products, personal care items and agriculture.

However, antimicrobials have since proven to be a double-edged sword, with AMR becoming one of the top global public health threats, according to the World Health Organization.

AMR is the ability of microorganisms – such as bacteria, fungi, viruses and parasites – to resist the killing capacity of antimicrobial drugs (e.g., antibiotics, antifungals, antivirals, etc). Although AMR encompasses all classes of microbes, the major research focus has been on antibiotic resistance in bacteria.

Driven by the misuse and overuse of antimicrobials in humans, animals and plants, drug-resistant pathogens now threaten our ability to treat common infections and perform life-saving procedures, in addition to threatening food security.

“Our old drugs are becoming less and less effective as bacteria become more and more resistant to them,” explained Dr. Gerry Wright, a professor in McMaster’s Department of Biochemistry and Biomedical Sciences and a researcher at the university’s Michael G. DeGroote Institute for Infectious Disease Research. “About 4.5 million people die every year due to antibiotic-resistant infections, and it’s only getting worse.”

The need for new antimicrobial medicines is at an all-time high; the last new class of antibiotics hit the market nearly three decades ago. However, a soil sample from a backyard in Hamilton, Canada, could answer these pressing issues.

A backyard soil sample may hold great promise

The research team, led by Wright, found that lariocidin, a lasso peptide, holds great promise as an early antimicrobial drug lead. This is due to its ability to attack bacteria in a way that is different from other antibiotics.

Lariocidin inhibits a bacterium’s ability to grow and survive through binding directly to its protein synthetic machinery, in a completely new way to that previously seen.

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

Produced by a bacteria called Paenibacillus, lariocidin was initially retrieved from a soil sample collected in a backyard. Wright and team grew the soil bacteria for approximately one year, helping to reveal the slow-growing bacteria that would have otherwise been missed. They observed that Paenibacillus produced a new substance (lariocidin) that had a strong activity against other bacteria, including those typically resistant to antibiotics.

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

Wright and team are optimistic about lariocidin, not only due to its unique mode of action and activity against otherwise drug-resistant bacteria but also due to it ticking the right boxes. Lariocidin is not susceptible to existing mechanisms of AMR, it is non-toxic to human cells and it works well in an animal model of infection.

The long road to clinical use

The research team is now focusing on investigating ways to modify lariocidin and produce it in large enough quantities to allow for clinical development.

Although this is an exciting discovery, much time and resources are needed before lariocidin is ready for market, due to it being produced by bacteria. As Wright said: “bacteria aren’t interested in making new drugs for us”.

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

Reference: Jangra M, Travin DY, Aleksandrova EV, et al. A broad-spectrum lasso peptide antibiotic targeting the bacterial ribosome. Nature. 2025:1-9. doi: 10.1038/s41586-025-08723-7

This article is a rework of a press release issued by McMaster University. Material has been edited for length and content.