Significantly higher levels of the antibiotic resistant hospital superbug MRSA have been found in hospital Intensive Care Units, where the most seriously ill patients are treated, compared with units that treat less ill patients, according to a report from the HSE's Health Protection Surveillance Centre.

The 'Surveillance of MRSA in general intensive care units 2010' report also reveals large differences among hospitals in the availability and quality of single rooms to isolate patients found to have MRSA, and halt the spread of the infection to others.

Just four of the 33 intensive care units in the national survey said they could isolate all of their MRSA patients.

According to the 13-page report, four intensive care units have no single rooms.

Also, 36% of ICU units fall below the 2005 national guidelines, recommending that they having one single bed, for every four ICU beds.

While all ICU units with single rooms had hand sinks, less than half had an anteroom for health staff.

The report also says that there are differences in MRSA screening protocols, before admission between hospitals, which hinders direct comparisons of MRSA figures.

Hospitals laboratories are also using different MRSA screening methods with different levels of sensitivity.

The report notes that the prevalence of MRSA is significantly higher in level 3 ICUs, as these units cater for a more acute patient group, with a higher risk of acquiring MRSA prior to admission and post admission, due to increased intensity of care.

This compares with the lower level 2/3 ICU units, which often have a combination of coronary care and high dependency patients.

The prevalence of MRSA in Level 3 ICUs was over 9% and over 8% in Level 2 ICUs.

Of the 33 ICU units studied, 14 were Level 3 ICUs and 19 were Level 2/3 ICUs.

The HSE has said that the number of MRSA cases diagnosed nationally has almost halved in the last five years.

The latest figures show that 304 cases were confirmed last year.

Overall, the MRSA rates in intensive care units have decreased in recent years, according to the HSE. Last year the rate was 9.3% compared with 10.2% for 2009.