Researchers discover new antibiotic on leaf surface of a weed
Swiss researchers have discovered a new, antibiotic chemical substance on the leaf surface of a widespread field weed. Their results show that this microcosm hides many as yet unknown natural substances that could make new drugs possible.
The risk of multi-resistant germs is growing
The World Health Organization (WHO) recently warned of an increasing number of multi-resistant germs. The increase in resistance to antibiotics poses an ever greater danger to mankind. If such drugs no longer work, even small inflammations can become a great risk. If the problem is not soon brought under control, according to an older study, around ten million people could be killed by multi-resistant germs by 2050. A discovery by researchers from Switzerland could now offer opportunities to overcome existing antibiotic resistance.
Bacteria produce bacteria themselves
Many of the antibiotics used today have been developed on the basis of natural substances that bacteria produce themselves to ward off other bacteria. These substances were sought and found primarily in the soil.
Various scientists assume that active substances against resistant germs could continue to come from the earth.
Julia Vorholt and Jörn Piel from the Institute of Microbiology at the Swiss Federal Institute of Technology (ETH) Zurich have now turned to a completely different ecosystem: the leaf surface of plants.
In a project supported by the Swiss National Science Foundation (SNSF) as part of the National Research Program "Antimicrobial Resistance" (NRP 72), they are studying bacterial strains from the leaf surface of the arable cress (Arabidopsis thaliana).
This microcosm, called the phyllosphere, is very low in nutrients. "This leads to great competitive pressure," Vorholt is quoted in a statement from the SNSF.
"That is why bacteria produce a wide variety of substances that they use to defend their living space."
Because despite the scarce food supply, a large number of organisms populate the phyllosphere. Vorholt and Piel examined more than two hundred strains of bacteria, all of which are found on the wild plant arable cress in Europe.
Overcoming existing resistances
Although the genomes of the strains were deciphered, they have so far hardly been analyzed in a targeted manner.
The scientists found a total of 725 antibiotic interactions between different strains, which lead to certain bacteria no longer multiplying.
"The big question was, of course, whether we only found substances that are already known from other habitats, or whether we came across compounds with completely new properties," said Piel.
This would be extremely important for antibiotic research: it is looking for new antibiotics with mechanisms of action that differ significantly from those of current medicines and thus overcome existing antibiotic resistance.
Absolutely new chemical structure
In order to determine whether new antibiotics were available, the Swiss researchers had to study the exact chemical compositions in detail.
They did this for gene clusters and substances from a single bacterial strain that has proven to be a particularly active producer.
In doing so, they discovered several antibiotic chemicals. One of them, named by the researchers Macrobrevin, has an absolutely new chemical structure.
The results of the study were published in the "Nature Microbiology" magazine.
Expand search for antibiotics in nature
"We will now clarify whether Macrobrevin and other newly discovered substances are also effective against bacteria that cause diseases in humans," says Piel.
However, he rates the success even more than this possibility of having shown that there are still a lot of natural products for antibiotics to be discovered in the little-researched phyllosphere:
“This incredibly diverse ecosystem can certainly provide a great many new approaches to medicine. Our results confirm that it is worth expanding the search for antibiotics in nature. ”(Ad)