An outbreak of the most virulent form of the superbug Clostridium difficile has contributed to the deaths of 17 elderly patients at a Norfolk hospital.

Officials at the James Paget University hospital said that the presence of the bug was a "major concern". The 026 strain of C diff is among the hardest of the antibiotic-resistant superbugs to control.

The patients have all died since December. Another 11 patients are still being treated for infections and five have had major bowel surgery to remove their infected organs.

Nick Coveney, director of nursing and patient services at the hospital, said a "wide-ranging infection control programme" had been put in place.

"C diff is causing us major concern at the moment," he said.

"We have a particularly virulent strain of C diff in the hospital and wider community."

"This strain of C diff is much more virulent than any strain we have experienced previously."

Last month the Office for National Statistics reported that 3,800 people died in 2005 after contracting C diff but the latest outbreak is the rarer 026 strain.

The bug is unique in that when traditional cleaning methods - which kill other superbugs - are used it can form spores which are far more hardy.

The strain has been recorded in Leicester, where 49 deaths at three hospitals were linked to it, and in Buckinghamshire. It is believed to have emerged first in Canada.