New strategy suggested in fight against antibiotic resistance

Blocking salmonella's biofilm production weakens bacterial community, making it easier to remove.

January 14, 2020

3 Min Read
KU Leuven biofilm.jpg
The antibacterial substance (top left) prevents the bacteria from cooperating, causing the biofilm to disappear.Credit: KU Leuven - MICA Lab

Bioscience engineers from KU Leuven, an autonomous university in Belgium, have developed a new antibacterial strategy that weakens bacteria by preventing them from cooperating. Unlike with antibiotics, there is no resistance to this strategy, because the non-resistant bacteria outnumber resistant ones, the university said in an announcement.

The findings were recently published in Nature Communications.

Traditional antibiotics kill or reduce the activity of individual bacteria, the researchers said, but some bacteria become resistant to these antibiotics, allowing them to grow further and take over from non-resistant ones.

Bacteria also exhibit group behavior, however. For example, they can make a protective slime layer or biofilm that envelops their entire bacterial community. Biofilms are often the source of bacterial infections, the researchers said. The social behavior of bacteria is an interesting new target for antibacterial therapy.

Stronger together, weaker alone

The researchers showed that blocking biofilm production of salmonella bacteria weakens the bacterial community, making it easier to remove. They used a chemical, antibacterial substance that was previously developed at KU Leuven.

"Without their protective slime layer, the bacteria can be washed away by mechanical forces and killed more easily by antibiotics, disinfectants or the immune system," said MICA Lab professor Hans P. Steenackers, lead author of the study.

The university said the scientists then compared the development of bacterial resistance to the new substance with that of classical antibiotics in a so-called evolution experiment. Evolution experiments are used to see how microorganisms adapt to a certain situation.

"We saw that the bacteria, as a group, did not become resistant to our antibacterial substance, while this did happen with antibiotics -- and quickly so," Steenackers explained. "Moreover, we showed those bacteria that were resistant to the new antibacterial substance became outnumbered by non-resistant ones."

A resistant bacterium will still be able to produce slime and share this with the non-resistant bacteria in the group. However, this costs energy, while the non-resistant bacteria benefit from the protection free of charge. As a result, non-resistant bacteria can grow faster than the resistant ones so that their share increases compared to the resistant bacteria.

"In contrast to traditional antibiotics, this substance ... does not cause selection for but against resistance," Steenackers said. "Antimicrobial treatments that stop bacteria from working together can, therefore, be a viable solution to the current problem of antibiotic resistance."

Pill or coating

Steenackers said the researchers' "aim is to introduce these new antimicrobials into clinical practice. They can be used as a preventive medicine in the form of a pill or as a coating on implants to reduce the risk of infections." The substance could also be used together with antibiotics.

Furthermore, several agricultural, industry and household applications are possible. To this end, the researchers are collaborating with experts in various applications and with producers of animal feeds and cleaning products and disinfectants. The researchers are also investigating whether they can reproduce the phenomenon in other forms of microbial collaboration next to biofilms and with other bacteria.

"In the long term, this concept can also be used to develop alternatives to antibiotics," Steenackers concluded.

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