MRSA rates at Oxfordshire's major hospital almost doubled in March, although experts claim the increase is random and patients have nothing to fear.

There were 17 cases of the bug within the Oxford Radcliffe Hospitals NHS Trust, compared to nine in the previous month.

Methicillin resistant Staphylococcus aureus is a bug that has evolved resistance to antibiotics, and attacks the sick and vulnerable in hospital, whose immune systems are too weak to battle against it.

Infection control specialist Dr Derrick Crook said although staff had looked at the sudden rise in numbers, it was well-known that variations could be random on a month-to-month basis, and figures had to be looked over the long term.

He said: "Even if you have a decreasing rate of infection you could vary from as many as 25 on a bad month down to as few as two or three on another.

"The shorter the period you look at, the more you can be misled."

Of the 17 new cases in March, 12 were identified in general medicine and the kidney disease department, but experts found nothing to link them.

Dr Crook said that kidney dialysis patients, whose blood was routinely 'cleaned' through a machine, were susceptible to infection, while patients in general medicine were usually more vulnerable to infection than other people.

He added: "These figures still make up a tiny proportion of all our patients. We treat 48,000 emergency patients and have about 20,000 inpatients coming in for treatment.

"We also did a study recently showing that a third of patients infected with MRSA come in from the community with the bacteria."

During the last financial year, the ORH had a target to lower MRSA infections to 89 or fewer.

But they failed to meet the goal by 11. Dr Crook said: "To be 11 over the target is not that bad. Two thirds of the country's hospital trusts didn't make their targets."