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Antimicrobial resistance (AMR) is a growing global threat. It already contributes to around 4.95 million deaths each year, with bacteria increasingly outsmarting the antibiotics we've relied on for decades.
But a recent discovery in an unlikely place—a backyard in Hamilton, Canada—may offer new hope.
Scientists have identified a new class of antibiotics called lariocidin, a lasso-shaped peptide that blocks bacterial protein synthesis in a completely different way than current drugs. That’s a big deal, because bacteria haven’t had a chance to develop resistance to it yet.
This is the first new antibiotic class discovered in nearly 30 years. Researchers isolated lariocidin from a strain of Paenibacillus bacteria found in soil. After a year of lab work, they found lariocidin could kill several harmful bacteria, including drug-resistant strains, without harming human cells or triggering resistance mechanisms.
How Lariocidin Works
Lariocidin is part of a rare group of molecules called lasso peptides—tiny, stable compounds made by bacteria. While some lasso peptides have shown antibacterial potential before, lariocidin is the first known one to directly attack the bacterial ribosome, the machinery bacteria use to make proteins.
It works by binding to a unique site on the ribosome’s small subunit, interfering with two key steps in protein production: decoding and translocation. This stops bacteria from growing.
It avoids known resistance pathways, shows low risk of resistance developing, and hasn’t shown toxicity in human cells. In mouse studies, it successfully treated serious infections like Acinetobacter baumannii.
This discovery opens the door to a new class of antibiotics—a badly needed tool in the fight against superbugs.
What Makes Lariocidin Different
Lasso peptides are natural molecules made by certain bacteria. They have a unique knot-like structure, making them very stable and resistant to heat and breakdown. This stability makes them interesting for fighting infections.
Researchers have been studying lasso peptides for their potential as antibiotics. Many can affect bacterial processes, but lariocidin is the first known lasso peptide to directly target the bacterial ribosome, the part of the cell that makes proteins. It stops bacterial growth by blocking key steps in protein production.
This discovery is important because antimicrobial resistance (AMR) is a growing global threat. AMR happens when bacteria become resistant to the drugs meant to kill them. The problem is getting worse because no new class of antibiotics has been approved in nearly 30 years. Most current antibiotics are just variations of old drugs, and bacteria are evolving to resist them.
This is important because it offers a new type of antibiotic that targets bacteria in a fresh way. It provides hope that new antibiotics could help us fight resistant bacteria.
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References
- American Chemical Society. (2020). Lasso peptides and their potential as antibiotics. ACS Nano, 14(9), 11872-11879. https://pubs.acs.org/doi/10.1021/acsnano.4c11443?goto=supporting-info
- The Lancet. (2021). The burden of antimicrobial resistance in the world: A study of global mortality and morbidity. The Lancet. https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(21)02724-0/fulltext
- Nature. (2025). Lariocidin: A new antibiotic targeting bacterial ribosomes discovered in soil. Nature. https://doi.org/10.1038/s41586-025-08723-7