Objectives: To synthesize comparative studies that examined the benefits and harms of screening for methicillin-resistant Staphylococcus aureus (MRSA) carriage in the inpatient or outpatient setting.
Data sources: MEDLINE®, Embase®, the Cochrane Database of Systematic Reviews, the National Institute for Clinical Excellence, the National Guideline Clearinghouse, and the Health Technology Assessment Programme were searched from January 1990 to March 2012. A search of the gray literature included databases with regulatory information, clinical trial registries, abstracts and conference papers, grants and federally funded research, and information from manufacturers.
Review methods: We sought studies that compared MRSA screening strategies, including universal screening; screening of selected patient populations (surgery, intensive care unit, high risk); and no screening. Outcomes were MRSA acquisition; MRSA infection; morbidity (including complications of MRSA infection); mortality; adverse events (including allergic and nonallergic toxicity [e.g., hypotension], antimicrobial resistance, reduced quality of care, and medical errors); and hospital resource utilization, such as length of stay. Data were abstracted by a team of reviewers and fact-checked by another team of reviewers. Study quality was assessed using the U.S. Preventive Services Task Force framework. Strength of the body of evidence was assessed according to the Agency for Healthcare Research and Quality “Methods Guide for Effectiveness and Comparative Effectiveness Reviews.”
Results: Forty-eight studies were abstracted for this review. Of these, only 1 was a randomized controlled trial; the other 47 studies utilized quasi-experimental study designs. Sixteen of the studies attempted to control for confounding and/or secular trends, and therefore had the potential to support causal inferences about the impact of MRSA screening on health outcomes and to contribute to the strength-of-evidence syntheses. This review found low strength of evidence that, compared with no screening, universal screening for MRSA carriage reduces healthcare-associated MRSA infection. For each of the other screening strategies evaluated, this review found insufficient evidence to determine the comparative effectiveness of screening on MRSA acquisition or infection.
Conclusions: There is low strength of evidence that universal screening of hospital patients decreases MRSA infection. However, there is insufficient evidence on other outcomes of universal MRSA screening, including morbidity, mortality, harms, and resource utilization. There is also insufficient evidence to support or refute the effectiveness of MRSA screening on any outcomes in other settings. The available literature consisted mainly of observational studies with insufficient controls for secular trends and confounding to support causal inference, particularly because other interventions were inconsistently bundled together with MRSA screening. Future research on MRSA screening should use design features and analytic strategies addressing secular trends and confounding. Designs should also permit assessment of effects of specific bundles of screening and infection control interventions and address outcomes, including morbidity, mortality, harms, and resource utilization.