Hereford County Hospital is keeping up a vigorous hygiene campaign to combat a new and potentially fatal superbug that has been linked to the deaths of four patients over the past month.

Most at risk from the bug C.diff - Clostridium difficile - are patients treated with the kind of common antibiotics used to kill infections and tackle other illnesses.

C-diff takes the form of diarrhoea, is highly infectious and can contribute to the death of people already suffering serious illness.

Between two and 18 cases a month have been reported at Hereford County Hospital this year, but most people can be treated to make a full recovery.

However, some patients had been infected with C.diff that had been part of the sequence leading up to their death, said Helen Blanchard, director of nursing at Hereford Hospitals Trust.

Herefordshire coroner David Halpern said that C-diff had started showing up as a contributory cause of deaths referred to his team by the County Hospital.

Four deaths from natural causes this month could be linked to the bug, but, so far, there was no evidence that C-diff was a primary cause of death, said Mr Halpern.

"This in not MRSA but something new and it seems worse in Hereford at the moment," he said.

C-diff usually strikes the elderly who are ill and frail. The antibiotics can disturb the balance of normal bacteria in the gut, causing diarrhoea of varying severity.

Across the country numbers of cases had doubled from 20,556 to 43,682 in five years, although the big increase could be put down to increased testing at reporting.

Mrs Blanchard said the situation at the County was being monitored daily. All patients who became victims were being tracked to see if there were common factors.

Patients with C.diff were isolated, staff had to wear protective clothing and there was an intense programme of education to ensure people washed their hands as well as using the new protective gels. Hygiene at the hospital was a continuing top priority.

She confirmed that many of the cases were usually caused by common antibiotic treatment and that older, more frail people with other ailments were most at risk.

Doctors were being made aware of the situation and advised to use other forms of antibiotics whenever possible.

In the majority of cases, patients affected with C.diff diarrhoea could be effectively treated with specific oral antibiotics and made a full recovery.

"Hereford Hospitals NHS Trust take the problem of C.difficile very seriously. There is an antibiotic policy in place and all doctors have been advised about avoiding those which are associated most with disturbing the bacteria in the gut, and therefore increasing the likelihood of an overgrowth of C.difficile,'' said Mrs Blanchard.

She said that the outbreaks of diarrhoea at the hospital last year that caused wards to be closed and surgery to be cancelled were of a different variety.