Tough spores make infection hard to prevent and to treat

Public alarm over hospital-acquired infections has focused on MRSA (methicillin resistant staphylococcus aureus) but the "superbug" accounts for about 7,000 - of estimated 300,000 infections a year.

Public alarm over hospital-acquired infections has focused on MRSA (methicillin resistant staphylococcus aureus) but the "superbug" accounts for about 7,000 - of estimated 300,000 infections a year.

Clostridium difficile is the commonest cause of diarrhoea in hospitals and can lead, in severe cases, to inflammation of the gut similar to gas gangrene. It is not resistant to antibiotics but some patients are difficult to treat. Cases of C. difficile are rising rapidly while cases of MRSA have begun to fall.

The bacteria is present naturally in the intestines of healthy individuals where it is kept under control by the presence of other bacteria. When antibiotics are given as part of other routine hospital treatment they may knock out some bacteria, allowing C. difficile to take advantage. Thus drugs given to protect patients against infection may make them more vulnerable to it.

Overuse of antibiotics is thought to be key reason for the dramatic rise in cases of C. difficile. It mainly attacks the elderly and vulnerable but the new more virulent strain identified at Stoke Mandeville hospital has also affected younger patients.

Andrew Berrington, a consultant microbiologist at Sunderland City hospital and a member of the National C. difficile Standards Group set up by the Department of Health, said: "Although cleaning and hygiene are important the main problem is antibiotic use. People are given antibiotics when they don't need them and when they need them they are given the wrong ones."

Cephalosporins, powerful antibiotics used to treat surgical, urinary tract and respiratory infections, were more likely to cause infections with C. difficile, he said. Treatment ofC. difficilie is with another antibiotic such as metronidazole or vancomycin. Professor Peter Boriello, of the Health Protection Agency, said the rise in C. difficile infections was partly due to better reporting by laboratories. "There are reports from Canada and the US this strain at Stoke Mandeville has caused particular problems."

Alcohol hand gels introduced for cleansing between patients was meant to be convenient and compensate for a lack of sinks. But it was not adequate to deal with C. difficile, which creates spores difficult to destroy.