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Archived: This report is greater than 3 years old. Findings may be used for research purposes, but should not be considered current.
This report is from AHRQ's series on Future Research Needs Projects.
Methicillin-resistant Staphylococcus aureus (MRSA) emerged as a clinically relevant human pathogen more than 5 decades ago. The virulent bacterium was first detected in hospitals and other health care facilities where vulnerable hosts, frequent exposure to the selective pressure of intensive antimicrobial therapy, and the necessity for invasive procedures created a favorable environment for dissemination. MRSA emerged as an important cause of health care-acquired infections, particularly central line-associated bloodstream infection, ventilator-associated pneumonia, and surgical site infection.
Despite the adoption of infection control measures, the incidence of MRSA infection at most hospitals in the United States (U.S.) steadily increased for many years, but is now decreasing. Routine clinical cultures may miss a large portion of patients who are silent carriers of these organisms and serve as reservoirs for further transmission. More aggressive measures have been sought to check the spread of this particularly virulent pathogen. Active surveillance screening for MRSA is receiving greater attention for its potential value in identifying carriers of MRSA to prevent further transmission.
To identify the population of colonized individuals, microbiological samples are obtained from at-risk patients even in the absence of signs or symptoms of infection. The screening strategy may use a testing modality with a rapid turnaround time (results available on the same day as the testing is performed, typically using polymerase chain reaction (PCR), intermediate turnaround time (results available next day to 2 days after testing performed) or longer turnaround time (results available greater than 2 days after testing performed, typically culture). Because screening alone is not expected to affect health outcomes, screening strategies may include screening with or without isolation and with or without attempted decolonization or eradication. By detecting the larger population of colonized individuals, at the very least conventional precautions (i.e., hand hygiene and contact isolation) can be implemented in a broader and timelier manner to interrupt horizontal transmission of MRSA. Detection of colonized patients also permits consideration of more aggressive interventions, including attempts at microbiological eradication or decolonization.
A Comparative Effectiveness Review (CER) was prepared by the Blue Cross and Blue Shield Association Technology Evaluation Center Evidence-based Practice Center (BCBSA TEC EPC) on Screening for Methicillin-Resistant Staphylococcus aureus (MRSA). The objective of the CER was to synthesize comparative studies that examined the benefits or harms of screening for MRSA carriage in the inpatient or outpatient settings. The review examined MRSA-screening strategies applied to all hospitalized or ambulatory patients (universal screening), as well as screening strategies applied to selected inpatient or outpatient populations (e.g., patients admitted to the intensive care unit (ICU), patients admitted for a surgical procedure, or patients at high-risk of MRSA colonization or infection such those on prolonged antibiotic therapy) and compared them to no screening or to screening of selected patient populations (targeted screening). The review evaluated MRSA-screening strategies with or without isolation and with or without attempted eradication/decolonization.