Scientists in the United States have developed a vital tool in the battle against superbugs by re-engineering a decades-old antibiotic.

A modified version of the antibiotic vancomycin is believed to be much more effective at fighting Enterococci bacteria, which is found in hospitals and can cause dangerous wound and blood infections.

It could be years, however, before the completion of clinical trials needed to turn the lab discovery into a mass-produced medicine, Dr. Andrew Edwards, a lecturer in molecular microbiology at Imperial College, London, told CNN.