Super-resistant bugs on increase

New evidence of the growth of superbugs resistant to all known antibiotics has been found by scientists who have identified strains of a common bacterium that is able to evade the last line of defence against infection.

The bacterium, Staphylococcus aureus, can cause fatal disease and strains resistant to the antibiotic methicillin have been known since the 1970s. This left only vancomycin as the last antibiotic to which the organism was susceptible.

Earlier this year a vancomycin-resistant strain of S aureus was found in Japan which meant some infections with the organism might be untreatable. However, it was not clear how common such strains might be.

Now the researchers from Juntendo University, Tokyo, report a study of more than 1,000 strains of methicillin-resistant isolated from patients in 203 hospitals in Japan. Writing in the Lancet, they say they found no new strains that were completely resistant to vancomycin but they did find strains with variable resistance, where a proportion of the organisms within the strain were not susceptible to the antibiotic.

In their own Juntendo University hospital, vancomycin resistance was found in 20 per cent of the bacterial strains. They concluded: "There is a need for special precautions to limit the spread of [resistant] strains in Japan (and the world)."

In a commentary, Dr Soad Tabaqchali of St Bartholomew's Hospital, London, says affected patients should be isolated to prevent spread, and overprescribing of antibiotics must be halted to prevent the further growth of resistance.