The last time a new class of antibiotics arrived on the market was almost three decades ago, but the situation could soon change, thanks to a discovery of the Canadian researchers of McMaster University. A team led by Gerry Wright has identified a valid candidate to challenge some of the most resistant to drug bacteria: it is a new molecule called lariocidine.
The results – published in the magazine Nature On March 26, 2025 – they could open the door to a brand new antibiotics class and respond to the need – increasingly critical – of new antimicrobial drugs, since bacteria and other microorganisms develop new ways to resist existing drugs causing infections that led to mortality rates up to 40%.
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According to the World Health Organization, antimicrobial resistance is one of the main threats to public health worldwide. “Our old drugs are becoming less and less effective because bacteria become increasingly resistant to them” explains Gerry Wright, professor at the Biochemistry Department and biomedical sciences of McMaster. “About 4.5 million people die every year due to antibiotic resistant infections, and the situation only worsens”.
Wright and his team have discovered that the new molecule, a peptide lasso, is very promising as a driver drug because it attacks the bacteria in a different way from other antibiotics.
“It is a new molecule with a new way of action – says Wright – a big step forward for us”.
Lariocidine is directly linked to the protein synthesis mechanism of a bacterium in a completely new way, inhibiting its ability to grow and survive.
lariocidine produced by the Bacterium Paenibacillus
Lariocidine is produced by a type of bacterium called Paenibacillus that the researchers have recovered from a land of land collected in the courtyard of the Canadian town of Hamilton where the McMaster University is located.
The research team let soil bacteria grow in the laboratory for about a year, a method that has also contributed to revealing the slow growth species that otherwise could have passed unnoticed. One of these bacteria, the Paenibacillus, was producing a new substance with a strong activity against other bacteria, including those usually resistant to antibiotics.
“When we understood how this new molecule kills other bacteria, it was a turning point”
In addition to its single way of action and its activity against bacteria otherwise resistant to drugs, researchers are optimistic on lariocidine because they meet many of the requirements for transformation into a drug: it is not toxic to human cells, it is not susceptible to current antibiotic resistance mechanisms and has worked in an animal test.
Wright and his team are now focused on the search for ways to change the molecule and produce it in large enough quantities to allow clinical development. Wright states that since this new molecule is produced by bacteria (and “bacteria are not interested in producing new drugs for us”), a lot of time and resources are needed before lariocidine is ready for the market.
“Now the real hard work begins,” says Wright who is analyzing the molecule to look for a way to summarize it chemically.