Costs and Benefits of Rapid Screening of Methicillin-resistant Staphylococcus aureus Carriage in Intensive Care Units

A Prospective Multicenter Study

Marjan Wassenberg; Jan Kluytmans; Stephanie Erdkamp; Ron Bosboom; Anton Buiting; Erika van Elzakker; Willem Melchers; Steven Thijsen; Annet Troelstra; Christina Vandenbroucke-Grauls; Caroline Visser; Andreas Voss; Petra Wolffs; Mireille Wulf; Ton van Zwet; Ardine de Wit; Marc Bonten


Crit Care. 2012;16(R22) 

In This Article

Abstract and Introduction


Introduction Pre-emptive isolation of suspected methicillin-resistant Staphylococcus aureus (MRSA) carriers is a cornerstone of successful MRSA control policies. Implementation of such strategies is hampered when using conventional cultures with diagnostic delays of three to five days, as many non-carriers remain unnecessarily isolated. Rapid diagnostic testing (RDT) reduces the amount of unnecessary isolation days, but costs and benefits have not been accurately determined in intensive care units (ICUs).
Methods Embedded in a multi-center hospital-wide study in 12 Dutch hospitals we quantified cost per isolation day avoided using RDT for MRSA, added to conventional cultures, in ICUs. BD GeneOhm™ MRSA PCR (IDI) and Xpert MRSA (GeneXpert) were subsequently used during 17 and 14 months, and their test characteristics were calculated with conventional culture results as reference. We calculated the number of pre-emptive isolation days avoided and incremental costs of adding RDT.
Results A total of 163 patients at risk for MRSA carriage were screened and MRSA prevalence was 3.1% (n = 5). Duration of isolation was 27.6 and 21.4 hours with IDI and GeneXpert, respectively, and would have been 96.0 hours when based on conventional cultures. The negative predictive value was 100% for both tests. Numbers of isolation days were reduced by 44.3% with PCR-based screening at the additional costs of €327.84 (IDI) and €252.14 (GeneXpert) per patient screened. Costs per isolation day avoided were €136.04 (IDI) and €121.76 (GeneXpert).
Conclusions In a low endemic setting for MRSA, RDT safely reduced the number of unnecessary isolation days on ICUs by 44%, at the costs of €121.76 to €136.04 per isolation day avoided.


Nosocomial infections caused by methicillin-resistant Staphylococcus aureus (MRSA) have been associated with increased mortality and high health care costs.[1,2] There is considerable geographic variation in the prevalence of nosocomial MRSA infections. In intensive care units (ICUs) in the US the prevalence of MRSA among clinical S. aureus isolates is over 55%,[3,4] while in countries with a national search and destroy policy for MRSA, such as Scandinavian countries and the Netherlands, the prevalence among bacteremia isolates is still around 1%.[5] Pre-emptive isolation of patients considered at high risk for MRSA carriage is considered a cornerstone of such a control policy and has been shown to reduce ICU acquired MRSA infections in medical ICUs.[6] However, the vast majority of patients considered at increased risk for carriage will not be colonized with MRSA, yielding considerable amounts of unnecessary isolation days as conventional microbiological culture methods have a diagnostic delay of three to five days. Isolation measures are costly[7,8] and may compromise the quality of patient care.[9]

Rapid molecular screening for MRSA carriage may reduce the logistical and financial burdens associated with pre-emptive isolation of ICU patients. However, the costs and effects of such diagnostic tests have not been determined for use in ICUs.[10] Therefore, we quantified costs and benefits of two rapid screening tests for MRSA on ICUs in a multi-center study in the Netherlands.


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