MRSA Prevention Strategies Analyzed, Screening Policies Challenged

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July 18, 2013

A large, new study may prompt changes to the way hospitals protect patients from serious infections during their stay. Findings from the study, published in the June 13, 2013 issue of the New England Journal of Medicine, indicated that decontaminating all intensive care unit (ICU) patients using procedures intended to remove bacteria from the skin and from within the nose was the most effective of the three strategies that were evaluated.

Infections acquired while in the hospital put many patients, especially those in ICUs, at risk of serious illness. Hospitals commonly take precautions to avoid spreading infections, including those caused by drug-resistant bacteria. Methicillin-resistant Staphylococcus aureus (MRSA) is one example of drug-resistant bacteria that can cause life-threatening infections such as pneumonia, bloodstream infections, or infections at a surgical site.

Currently, hospitals typically screen ICU patients for MRSA on admission and implement contact precautions (called contact isolation) if they are found to carry the bacteria (colonized). Nine states mandate such screening. Contact isolation may involve separating those who are colonized into single-patient rooms with limited movement of the patient outside their room, use of gowns, gloves, and masks for health care providers treating them, use of disposable or patient-dedicated equipment, and frequent cleaning and disinfection of the surrounding environment. Decontamination (decolonization) of patients found to be carriers of the bacteria usually includes use of an antibiotic ointment (mupirocin) within the nasal passages and bathing with cloths containing the antimicrobial chlorhexidine soap.

For the study, over 74,000 patients from 43 hospitals were included in the evaluation of three strategies for the prevention of hospital-acquired infections such as MRSA. All patients in the ICU at a particular hospital were assigned to one prevention strategy, and hospitals were randomly assigned to one of the three strategies:

  • Group 1 received MRSA screening and isolation for those testing positive.
  • Group 2 received MRSA screening and isolation as well as decolonization of MRSA carriers ("targeted decolonization").
  • Group 3 received decolonization of all patients – without MRSA screening or isolation ("universal decolonization").

The researchers reported that universal decolonization (Group 3) resulted in significantly greater reduction in the rate of all bloodstream infections than either targeted decolonization (Group 2) or screening and isolation (Group 1). MRSA-positive cultures were reduced by 37% and bloodstream infections caused by any disease-causing bacteria (pathogen) were reduced by 44% in Group 3.

Implementing a strategy of universal decolonization has several additional benefits. For example, patients do not need to be isolated from others in the ICU and there would be no delay in decolonizing while waiting for culture results, during which time carriers could infect others.

Some hospitals have already started implementing changes to policy because of these findings. Of course, those states that have a regulatory requirement for MRSA screening would need to have that changed before their hospitals could adopt a "no MRSA screening" policy. Drs. Michael Edmond and Richard Wenzel stated in an editorial in the same issue of the journal that, "The implications of this study are highly important. The lack of effectiveness of active detection and isolation should prompt hospitals to discontinue the practice for control of endemic MRSA…the folly of pursuing legislative mandates when evidence is lacking has been shown, and laws mandating MRSA screening should be repealed."

The researchers plan to investigate in a second phase of the study whether universal decolonization might cause an increase in resistance to the antibiotic medications used (mupirocin, chlorhexidine). They warn that vigilance is needed at any institution implementing a universal decolonization strategy to detect any emerging resistance. However, given the clear benefits, more hospitals may opt to use this strategy, leading to fewer laboratory tests for MRSA screening and fewer ICU patients in contact isolation in the near future.

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NOTE: This article is based on research that utilizes the sources cited here as well as the collective experience of the Lab Tests Online Editorial Review Board. This article is periodically reviewed by the Editorial Board and may be updated as a result of the review. Any new sources cited will be added to the list and distinguished from the original sources used.

Susan S. Huang, et al. Targeted versus Universal Decolonization to Prevent ICU Infection. NEJM 368;24. June 13, 2103.

Michael B. Edmond, M.D., M.P.H., and Richard P. Wenzel, M.D. Screening Inpatients for MRSA — Case Closed. NEJM 368;24. June 13, 2013.

Landro, L. New Tack in Preventing Hospital Infections: Germ-Killing Soap-Ointment Treatment for all ICU Patients Shown to Be More Effective Than Isolating Some After Screening. Wall Street Journal. Thursday, May 30, 2013, page A7. Available online at http://online.wsj.com/article/SB10001424127887324682204578513393292747314.html through http://online.wsj.com. Accessed July 2013.

Centers for Disease Control and Prevention. Methicillin-resistant Staphylococcus aureus (MRSA) Infections. Available online at http://www.cdc.gov/mrsa/ through http://www.cdc.gov. Accessed July 2013.

Centers for Disease Control and Prevention. Precautions to Prevent the Spread of MRSA in Healthcare Settings. Available online at http://www.cdc.gov/mrsa/prevent/healthcare/precautions.html through http://www.cdc.gov. Accessed July 2013.