The MRSA infection can be fatal

Nearly three quarters of those deaths occurred in the over-75 age group.

A study by the Communicable Disease Surveillance Centre also showed that levels of infection found in hospitals had risen.

More than 300 cases were discovered among patients in the last 12 months, compared just under 500 cases reported between 2001 and 2003.

The MRSA (methicillin resistant staphylococcus aureus) infection is a strain of skin and nose bacterium which has become resistant to commonly prescribed antibiotics.

Handwashing is key to reducing hospital infections

Dr Lorraine Doherty, the officer in charge of Communicable Diseases, said the level of MRSA in Northern Ireland hospitals was of great concern.

"We are addressing it in many ways which we hope will curb its rate of growth," she said.

"However, it is not always possible to observe clear improvements from such measures.

"We are not complacent and have in hand further developments such as the recently announced development of an infection control strategy for Northern Ireland."

The Department of Health revealed in July that MRSA had contributed to the deaths of 30 patients in Northern Ireland hospitals last year.

In the latest analysis of deaths - from 1997-2003 - where MRSA was recorded as a factor, the Northern Ireland Statistics and Research Agency listed 116 cases.

The Communicable Disease Surveillance Centre's third annual report backed the assessment that MRSA infection rates was increasing.

Vulnerable patients

The centre, based at Belfast City Hospital, used episodes of bloodstream infection to show the scale of infection.

Its study found a 35% rise from the first year of examining the bug and a 41% jump from 12 months ago, when levels dipped slightly.

Dr Doherty added: "It is clear from these figures that some parts of the health service have to do more to control this threat and match the achievements of hospitals which maintain low MRSA levels.

"It is an important reminder that everyone needs to keep infection control at the top of their agenda."

Patients on intensive care units and on surgical wards are among the most vulnerable to the bug.