The number of patients suffering from potentially lethal superbug infections at Oxfordshire's major hospitals has risen by more than a third since 2001.

But managers at the Oxford Radcliffe Hospitals NHS Trust said new Department of Health figures on MRSA cases reflected its role as a specialist organisation, looking after patients transferred from smaller hospitals who had already contracted the condition.

Their comments were backed up by a separate National Audit Office report on MRSA, which praised the trust's ward housekeeper scheme for improving cleanliness at its hospitals.

MRSA -- Methicillin resistant staphylococcus aureus -- first appeared in the 1960s. It usually affects elderly and vulnerable people, which is why it is commonly found in hospitals.

Some strains are resistant to most antibiotics. Fighting them costs the NHS an estimated £1bn a year.

According to the DoH, the ORH -- responsible for Oxford's John Radcliffe Hospital, Churchill Hospital and Radcliffe Infirmary, and The Horton, Banbury -- had 127 reported cases of MRSA between April 2003 and March this year -- 0.302 cases during every 1,000 bed days.

This is a 14 per cent rise since 2002-2003 when 114 patients were affected, and a 38 per cent increase since 2001-2002, when 92 cases were detected.

In the Government league table for the UK's 45 specialist hospitals, the ORH trust was ranked 12th worst. The best was Liverpool Women's Hospital, which had an MRSA rate of 0.067 cases per 1,000 bed days -- four times less than the ORH.

The NAO report praised the ORH's efforts to fight infections, including the trust's 35 ward housekeepers, who work with clinical staff to ensure wards are clean, as well as reporting damaged and broken equipment.

Sandy Clayton, senior nurse manager for infection control at the ORH, said: "Despite the figures, not all the cases reported are actually hospital acquired infections because paitents are transferred to us from all over the country.

"We are a major specialist centre, with major cardiology, radiology, and renal units, where very poorly patients are admitted from other hospitals, who may already have MRSA before they arrive."