DOCTORS at a London hospital believe they have encountered the ultimate "super bug ", a bacterium that only grows in the presence of a powerful antibiotic.
It mutated rapidly over a few days and became not only resistant to an antibiotic called vancomycin but dependent on it.
In a letter in The Lancet the scientists ask: "Have we at last witnessed the emergence of a true super bug ?"
Dr Ian Eltringham, a clinical microbiologist at St George's Hospital Medical School, south London, said yesterday: "Instead of the antibiotic being its poison it became its food."
He and his colleagues found the bacterium in two patients being treated on separate occasions with vancomycin.Their fevers did not abate and tests showed that the infection was enterococcus faecium, a common bacterium that lives naturally in the gut.
The first patient responded to other antibiotics and the second recovered when the vancomycin was stopped. "The worry is that our response when an antibiotic is not working is to give more of it. It would be better to stop the antibiotic and find out what is happening," he said.
