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Wednesday, February 14, 2024

Have scientists found a way to beat antibiotic resistance?

When bacteria become resistant to antibiotic treatments, this poses an important threat to health, as infections become very difficult — and sometimes impossible — to treat. But could a new strategy successfully identify the weak point of superbugs?

News Desk |

Antibiotic resistance, defined by bacteria’s lack of susceptibility to drugs that would otherwise be effective against them, has steadily become a significant problem at the global level, with scientists often referring to it as a crisis.

Researchers have been working to find solutions for this crisis, suggesting strategies as diverse as using bacteria-killing viruses or compounds derived from cranberries to attack drug-resistant bacteria, or “superbugs.” Most research into antibiotic resistance has focused on developing new pharmaceutical compounds or completely novel treatments that are not based on known antibiotics.

Looking more closely at heteroresistance could illuminate more aspects of antibiotic resistance and help identify promising ways to fight it.

However, researchers behind a new study from the Emory Antibiotic Resistance Center at the Emory University School of Medicine, in Atlanta, GA, believe that old drugs could be used in new ways to win the race against superbugs. The study’s authors explain that many bacteria have a type of resistance called “heteroresistance“, which many researchers still struggle to define precisely.

However, by and large, heteroresistance refers to a phenomenon in which, within a larger bacterial population, a subpopulation develops resistance to the antibiotic (or antibiotics) to which other bacteria in the same population respond. Moreover, since only a few bacteria within a population are drug-resistant, in the case of heteroresistance, doctors may find it hard to detect these instances using regular laboratory tests.

Read more: Can antibiotics control Alzheimer’s disease?

“We can think of heteroresistance as bacteria that are ‘half resistant,'” explains study co-author David Weiss, Ph.D. “When you take the antibiotic away, the resistant cells go back to being just a small part of the group. That’s why they’re hard to see in the tests that hospitals usually use,” he continues.

Weiss and colleagues believe that successfully identifying heteroresistance could help doctors and researchers identify which antibiotic combinations would work best in defeating a mixed population of susceptible and drug-resistant bacteria.

The idea of using antibiotic combinations to fight stubborn bacteria is by no means new, but studies such as the current one shed fresh light on why and how this strategy can be effective.

So far, laboratory experiments and research in mouse models — which the investigators present in Nature Microbiology — suggest that this approach could indeed help turn the tables against hard-to-track antibiotic-resistant bacteria.

‘Don’t toss those drugs in the trash’

Looking more closely at heteroresistance could illuminate more aspects of antibiotic resistance and help identify promising ways to fight it. The idea of using antibiotic combinations to fight stubborn bacteria is by no means new, but studies such as the current one shed fresh light on why and how this strategy can be effective.

Thus, the authors explain in their paper, “Multiple heteroresistance may explain a significant proportion of antibiotic combinations previously identified as synergistic [working in unison]”. Should heteroresistance to more than one antibiotic become combined within a bacterial strain, however, Weiss notes that the approach in the current study would be ineffective.

Read more: Can cranberries treat the antibiotic-resistance crisis?

Yet, for the time being, the researchers mean to take their experiments further and see how successful their approach can be in the case of other bacteria with heteroresistance. “We’re saying: Don’t toss those drugs in the trash, they may still have some utility. They just have to be used in combination with others to do so”.

While, “We can’t tell beforehand what combination will work [since] there isn’t any magic combination,” Weiss says, testing bacterial strains to figure out effective drug mixes “isn’t so much different from testing bacterial strains for resistance to individual antibiotics anyway,” rendering this strategy pragmatically viable.