Big Pharma had been closely interested in a compound dubbed acyldepsipeptide (ADEP), only to drop it when some germs became resistant to it.
But scientists in the United States reported that, when used alongside conventional antibiotics, ADEP proved to be a relentless killer.
"We decided to pair it to conventional antibiotics.... To stem the propagation of (drug) resistant cells," said study co-author Kim Lewis of Northeastern University in Boston.
The combination "completely sterilised" bacteria in a Petri dish and in mice whose thighs had been severely infected, said Lewis.
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Humans rely on antibiotics to fight off a vast array of bacterial diseases, from tonsillitis to tuberculosis.
But antibiotics do not work for all types of bacteria, and in some types where they are effective, germs are evolving worryingly into forms that are resistant to the drug.
Some infections are caused by biofilms -- slimy collections of bacterial cells that coat infected areas and block out the immune system, according to a podcast by Nature, accompanying the study in the British journal.
These are hibernating cells within the biofilm that stop dividing or growing and shut down their metabolism.
The dormant cells are the main cause of chronic and relapsing bacterial infections, since conventional antibiotics can target only actively growing bacterial cells.
"We had to look for something that in a persister will activate a function, will corrupt it, force it to kill the cell," said Lewis.