Universal MRSA Disinfection Cuts Infection Rates

Universal decolonization of all intensive care unit (ICU) patients as if they have methicillin resistant Staphylococcus aureus (MRSA) reduces infections substantially more than other more targeted strategies, according to a new study.

Researchers at the University of California Irvine (UCI; USA) conducted a pragmatic, cluster-randomized trial in 43 hospitals that were randomly assigned to one of three strategies, with all adult ICUs in a given hospital assigned to the same strategy. Group 1 implemented MRSA screening and isolation; group 2 implemented targeted decolonization involving screening, isolation, and decolonization of MRSA carriers; and group 3 implemented universal decolonization, with no screening. The researchers then assessed differences in infection reductions across the study groups, with clustering according to hospital.

In all, 74 ICUs and 74,256 patients were treated during the intervention period. The hazard ratio (HR) for MRSA clinical isolates were 0.92 for screening and isolation, 0.75 for targeted decolonization, and 0.63 for universal decolonization. In the intervention versus baseline periods, HRs for bloodstream infection with any pathogen in the three groups was 0.99, 0.78, and 0.56, respectively. Universal decolonization resulted in a significantly greater reduction in the rate of all bloodstream infections than either targeted decolonization or screening and isolation, with one bloodstream infection prevented per 54 patients who underwent decolonization. Adverse events, which occurred in seven patients, were mild and related to chlorhexidine. The study was published on May 29, 2013, in the New England Journal of Medicine.

“The universal decolonization arm involved a five day regimen of twice-daily intranasal mupirocin and daily bathing with chlorhexidine cloths for the duration of the ICU stay,” concluded lead author Susan S. Huang, MD, MPH, and colleagues. “In routine ICU practice, universal decolonization was more effective than targeted decolonization or screening and isolation in reducing rates of MRSA clinical isolates and bloodstream infection from any pathogen.”
The researchers cautioned that wide implementation of universal decolonization will require vigilance for emerging resistance to mupirocin, a topical antibiotic of the monoxycarbolic acid class which is bacteriostatic at low concentrations and bactericidal at high concentrations. MRSA resistance, if it becomes widespread, could destroy mupirocins value as a treatment, and may also result in overgrowth of nonsusceptible organisms.

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