In a large study of intensive care units (ICUs), universal decolonization proved more effective than rival strategies in reducing methicillin-resistant Staphylococcus aureus (MRSA)-positive clinical cultures and bloodstream infections from any pathogen.

In the REDUCE MRSA (Randomized Evaluation of Decolonization versus Universal Clearance to Eliminate MRSA) trial (N Engl J Med 2013;368:2255-2265), 43 hospitals (including 74 ICUs) were randomized to one of three groups. In the universal decolonization group, all patients underwent daily bathing with chlorhexidine-impregnated cloths and received twice-daily intranasal mupirocin for five days. In the screening and isolation group, patients’ nostrils were screened for MRSA on admission, and contact precautions were taken for patients with a history of MRSA or a positive MRSA test. In the targeted decolonization group, only patients known to have MRSA colonization or infection received a five-day decolonization regimen with mupirocin and chlorhexidine.

In the 18-month intervention period versus the 12-month baseline period, hazard ratios (HRs) for MRSA clinical isolates were 0.92 for screening and isolation, 0.75 for targeted decolonization and 0.63 for universal decolonization (P=0.01). In the intervention versus baseline periods, HRs for bloodstream infection with any pathogen were 0.99, 0.78 and 0.56, respectively (P<0.001). Universal decolonization significantly reduced MRSA-positive clinical cultures by 37% and bloodstream infections from any pathogen by 44%. There were seven adverse events, all mild (pruritus or rash) and related to chlorhexidine.

“The REDUCE MRSA trial helps answer a long-standing debate about how best to prevent superbugs,” Susan S. Huang, MD, MPH, an associate professor in the Division of Infectious Diseases, Health Policy Research Institute, University of California, Irvine School of Medicine, and the lead author, told Pharmacy Practice News. “One approach is to target high-risk bacteria—screen patients, find those who carry the superbugs and do something for them. Another approach is to target high-risk patients like those in ICUs and treat all of them as if they might have worrisome bacteria. We found that targeting all high-risk patients was the best strategy.”

The paper by Dr. Huang and her colleagues acknowledges that widespread use of chlorhexidine and mupirocin could promote resistance due to partial killing of colonizing organisms, with the surviving strains becoming resistant to future bactericidal treatments. This is the “biggest concern” of Kerry LaPlante, PharmD, an associate professor in the Department of Pharmacy Practice, College of Pharmacy, The University of Rhode Island in Kingston. Dr. LaPlante, who was not associated with the study, said the authors’ findings “are thought-provoking in many ways. But we must also stop and think about how the antimicrobials we recommend for a patient today directly impact how effective the same drug will be in another patient tomorrow. We have to be cautious and strategic in how we use antimicrobial agents. Basically, I don’t like universal anything when it comes to antimicrobial use—it stops thought processes.”

Dr. LaPlante added, “I feel these authors have a responsibility to the community to conduct a follow-up study in three to four years, showing what the MRSA chlorhexidine and mupirocin resistance rates are. Not until these data are published will I feel fully comfortable seeing this regimen used.”

In Dr. Huang’s view, “the question is whether we actually will breed resistance. We need to be attentive to this and monitor for it. But so far, resistance to mupirocin is infrequent and resistance to chlorhexidine is rare. If we do develop resistance, it’s important to remember that these topical products are only used to temporarily remove bacteria from the body, not to treat infections. We will not lose a therapeutic agent.”