Vancomycin, a type of antibiotic that's been prescribed for 60 years, may be the key to eliminating the threat of drug-resistant infections for years to come, say researchers at The Scripps Research Institute (TSRI).

Although vancomycin has been widely prescribed for more than half a century, bacteria are only now developing resistance to it. This suggests bacteria already have a hard time overcoming vancomycin's original "mechanism of action," which works by disrupting how bacteria form cell walls.

The researchers discovered a way to structurally modify vancomycin to make an already-powerful version of the antibiotic even more potent.

Lead researcher Dale Boger called vancomycin "magical" for its proven strength against infections, and previous studies by Boger and his colleagues at TSRI had shown that it is possible to add two modifications to vancomycin to make it even more potent. "With these modifications, you need less of the drug to have the same effect," he said.

The new study shows that scientists can make a third modification, which is a new way to interfere with a bacterium's cell wall. Combined with the two previous modifications, this alteration increases the activity of vancomycin 1,000-fold, meaning doctors could use much less of the antibiotic to fight infection.

The discovery makes this version of vancomycin the first antibiotic to have three independent mechanisms of action. "This increases the durability of this antibiotic," said Boger.

"Organisms just can't simultaneously work to find a way around three independent mechanisms of action," he said. "Even if they found a solution to one of those, the organisms would still be killed by the other two."

When tested against Enterococci bacteria, the new version of vancomycin killed both vancomycin-resistant Enterococci and the original forms of Enterococci.

"Doctors could use this modified form of vancomycin without fear of resistance emerging," said Boger.

The study's results were published in the journal Proceedings of the National Academy of Sciences.

German scientists are also on the trail of defeating superbugs that defy current antibiotics. They have created a new drug called lugdunin from a bacteria called Staphyloccus lugdunensis, which is present in the noses of about 10 percent of people. Tests have shown it is almost as powerful as the strongest drugs, and doesn't allow bacteria to mutate and develop resistance.