Health officials in the UK are closely monitoring a new strain of hospital infection following the deaths of 12 patients.
There have been some 300 cases of Clostridium difficile in 18 months at Stoke Mandeville Hospital, in Aylesbury, Bucks, a national centre for spinal injury, and it is thought that the infection was an "actual or probable" factor in 12 deaths in that time.
Elderly people are more at risk with the bug and the average age of the patients who died at Stoke Mandeville was 85.
Scientists at the UK's Health Protection Agency are checking to see if the virulent strain of the bacterial infection is Clostridium difficile 027, which has already been identified as the cause of infections in America and Canada.
According to a spokesman for the Buckinghamshire Hospitals NHS Trust, infection control staff noticed in late 2003 a rise in cases of the infection, which causes diarrhoea. He commented that in the 18-month period when the 300 cases were identified the hospital had been visited by 225,000 members of the public.
The spokesman says the trust's infection control team is working with the Health Protection Agency and the Strategic Health Authority on measures to combat the spread of Clostridium difficile.
Clostridium difficile is the most common cause of hospital infection and most people recover from it, but the elderly and those who have been on long courses of antibiotics are particularly at risk.
It is recommended that the infection be treated with two antibiotics, metronidazole and vancomycin. Some of the increase can be attributed to better reporting and more accurate identification, but cases have nevertheless risen sharply in recent years.
The marked increase made it mandatory for hospitals to report all cases of potential Clostridium difficile last year, and numbers have jumped from fewer than 1,000 cases in the UK in the 1990s to over 40,000 last year.
In 2003 there were 934 deaths, a similar number to those who died from the superbug, MRSA, in the same year.
Senior research fellow in medical microbiology at the University of Bath, Dr Mark Enwright, says that Clostridium difficile was easily spread between people and very hard to eradicate.
He says the most effective method would be to treat everyone in a ward, to close the ward and disinfect it thoroughly, with the pressure on beds in the NHS, this can be difficult.
Enwright says 50% of the population carry Clostridium difficile in their gut but it is kept in check by other bacteria, and problems arise when someone is on antibiotics, such as penicillin, which destroy these other bacteria.
The Health Protection Agency says symptoms are generally caused by the production of toxins in the large bowel and can range from a mild diarrhoea, which may be resolved once antibiotic treatment is stopped, through to severe colitis, an inflammation of the intestine, and life-threatening pseudo-membranous colitis, when the lining of the bowel breaks away.
A spokesman said they have received reports of this new strain and are watching it, but the available information indicates that the new strain is rare in the UK.