Hospital-acquired infections such as MRSA cannot be fully eradicated from Irish hospitals, according to the Health Service Executive (HSE).
Dr Kevin Kelleher, director of population health with the HSE, said research suggested "between half and two-thirds of healthcare-acquired infections are inevitable because of the service we are providing and who we are providing it to".
Currently one in every 20 patients (or around 5 per cent of patients) in Irish hospitals is estimated to have a hospital-associated infection at any given time.
Dr Kelleher said control measures should see hospital-acquired infection rates fall to "between 3 or 4 per cent" of the patient population, but they were unlikely to fall further.
Ireland's hospital-associated infection rate of 4.9 per cent compares with 8.2 per cent in English hospitals and 6.3 per cent in Wales, according to comparative research published last year. Dr Kelleher said it was likely current data underestimated the extent of such infections in Irish hospitals.
As part of its programme to deal with the issue, the HSE is recruiting 52 additional staff, including infection-control nurses and 20 antibiotic liaison pharmacists to help hospitals control infections.
These appointments have been delayed for several months due to the cap on healthcare recruitment.
Dr Kelleher said he hoped the recruitment of these staff would be complete by the summer.
MRSA is one of a number of antibiotic-resistant bacteria which can be life-threatening if it enters the bloodstream.
Although increasingly used as a generic term, MRSA accounts for about 10 per cent of all healthcare-acquired infections. In 2005 there were 592 MRSA infections in Irish hospitals. The number has been rising.
A second antibiotic-resistant superbug causing serious concern is Clostridium difficile. In 2005, more than 1,200 patients in Irish hospitals were diagnosed with Clostridium difficile. In severe forms it can lead to life-threatening complications.
Dr Robert Cunney, a consultant microbiologist at the Health Protection Surveillance Centre (HPSC), said the absence of a national surveillance system to monitor Clostridium difficile meant it was difficult to track infections and mutations.
Assessing the level of deaths caused by infections such as MRSA is difficult, not least because many patients contracting the infection are already seriously ill. The HSE says it does not have a figure for the number of deaths caused by such infections.
However, Dr Cunney said research of crude mortality data suggested patients with a severe MRSA infection were 15-30 per cent more likely to die. He stressed that many of those people "would have died as a result of their underlying illness".
"The contribution the antibiotic resistance bacteria makes to mortality is roughly two-fold," he said.
Last week a mutated strain of Clostridium difficile was identified in UK hospitals. Dr Cunney said a "handful" of infections from this strain of Clostridium difficile were identified in Irish hospitals last summer.
"We are not estimating it, because we don't have a system to measure these things," he said. "We don't have a reference laboratory that can provide the specialist test necessary to identify new strains."
To address this deficit, the HSE set up an expert advisory on Clostridium difficile late last year, chaired by a consultant microbiologist from the HPSC. This group will make recommendations on tackling Clostridium difficile.
Dr Cunney said healthcare- associated infections and antibiotic resistance could not be eradicated. "Only a third are preventable. It's a little like road traffic crashes. As long as you have roads and drivers, you'll have crashes.
"It's the same with healthcare- associated infections," he said.
