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New antibiotics haven’t been developed in decades, even as the rise of superbugs continues – partly because the accessible ones have already been discovered, and partly because the research and development efforts are cost prohibitive to many of the major pharmaceutical companies.

But a University of Texas at Austin team has a new way of filtering through potentially-breakthrough peptides that could become the antibiotics of the future, they say in a new study this month in the journal Cell.

Their method: a process of elimination by weeding out the bacteria in a test tube that are killed off by molecules tethered like a ball and chain to their surface, they write.

The new method, called Surface Localized Antimicrobial Display, or SLAY for short, the team of biologists screened roughly 800,000 molecules – and identified one particularly promising one called P7, they report.

“We thought, wouldn’t it be great if a bacteria could synthesize the compound for us, because bacteria are cheap and easy to grow, and then test the compound on itself and report back and tell us, was that an antimicrobial or not?” said Bryan Davies, leader of the UT Austin team of scientists.

The team engineered harmful bacteria - including 17 separate strains of E. coli - to produce a molecule on its membrane, connected by a tether ensuring that the two would interact as they floated around a test tube.

At the end of the experimental run, they would identify the remaining bacteria with next-generation sequencing. The bacteria that had been killed would flag the target peptides.

Thus, thousands of experiments run simultaneously, they say.

The P7 peptide was found to consistently kill pathogens – and the team plans to construct derivatives of it to test for the most effective versions, using the same testing method.

But it is the SLAY method itself that may be the big breakthrough in finding synthetic solutions to rising resistance, they write.

“SLAY hits present with different potential mechanisms of peptide action and access to areas of antimicrobial physicochemical space beyond what nature has evolved,” said Davies.

“What if we have a thousand groups all using this system to follow their own interests and their own peptides?” added Davies. “Once you enable a community of that size, then I think you have a better chance of actually finding a new antibiotic.”

The work drew some high-profile backing from both public and private sources, including the Defense Advanced Research Projects Agency and the National Institutes of Health, in addition to drug giant Sanofi and the U.S. Army Research Office.

Since the beginning of this century, the rise of antimicrobial resistance has been predicted to take a catastrophic toll of lives and resources. Already an estimated 20,000 people are killed per year by antibiotic resistance in the United States – but it could cause a full-scale global economic crisis by mid-century, according to a World Bank report released last year.

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