Rapid Test Identifies MRSA Carriers Earlier

A new molecular screening test for methicillin-resistant Staphylococcus aureus (MRSA) has shown the ability to substantially decrease the time between patients' admission to the medical intensive care unit (ICU) and the identification of MRSA carriers but had no effect on patients in the surgical ICU.

The test used was a quick multiplex immunocapture-coupled polymerase chain reaction (PCR) test called quantitative MRSA (qMRSA). The aims of the study were to assess whether the rapid test together with pre-emptive isolation could hasten the identification of MRSA carriers.

Traditional microbiologic methods for MRSA screening are slow. Delays in receiving screening results means either that negative patients remain isolated for too long or that positive patients remain a hidden reservoir for cross-infection. With the availability of rapid molecular MRSA screening methods, determining their value in daily practice is of great importance

The qMRSA test was used to systematically screen patients admitted to the ICU for longer than 24 hours. Median time intervals from admission to notification of test results were calculated for a five-month intervention phase and compared with those from a historical control period by nonparametric tests. ICU-acquired MSRA infection rates were determined for an extended surveillance period and analyzed by Poisson regression methods.

The study was carried out by Dr. Stephan Harbarth and colleagues from the Infection Control Program, Geneva University Hospitals (Geneva, Switzerland), and the results were reported in the February 2006 issue of Critical Care. These showed that the systematic on-admission screening and pre-emptive isolation policy was associated with a substantial reduction in medical ICU-acquired MRSA infections but was not effective in the surgical ICU. The qMRSA test decreased median time to notification from four days to one day and helped to rapidly identify previously unknown MRSA carriers.

The authors concluded that the molecular MRSA detection assay permits rapid identification of MRSA in critically ill patients. It could help to improve MRSA control strategies, especially when linked to systematic on-admission screening and pre-emptive isolation of newly admitted patients. Further controlled studies are necessary to evaluate its sustained impact on MRSA cross-infection.



Related Links:
Geneva University Hospitals