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Postdischarge MRSA Decolonization Cut Infection Risk

A 6-month methicillin-resistant Staphylococcus aureus (MRSA) decolonization protocol that included antiseptic cleansing of the skin, mouth, and nose reduced MRSA infections by 30% among colonized patients over 1 year of follow-up.

More than 2,000 patients colonized with MRSA at discharge from several Southern California hospitals from 2011 to 2014 were randomized to receive the 6-month decolonization protocol plus hygiene education or hygiene education alone, according to Susan Huang, MD, of the University of California Irvine School of Medicine, and colleagues.

In the per-protocol population, MRSA infection occurred in 98 of 1,063 participants (9.2%) in the education group and in 67 of 1,058 (6.3%) in the decolonization group; 84.8% of the MRSA infections led to hospitalization, they wrote in the New England Journal of Medicine.

Infection from any cause occurred in 23.7% of the participants in the education group and 19.6% of those in the decolonization group; 85.8% of the infections led to hospitalization, they also reported.

The decolonization intervention involved bathing with chlorhexidine antiseptic soap, use of chlorhexidine mouthwash, and use of the nasal antibiotic ointment mupirocin for 5 days twice a month for 6 months.

MRSA is responsible for more than 80,000 invasive infections in the U.S. each year, and it is the most common cause of skin, soft-tissue and procedure-related infections.

Huang told MedPage Today that it is now clear that patients who have MRSA infections, or positive cultures for MRSA during hospitalization, have an elevated risk of infections for around a year after discharge, with the highest risk occurring during the first 6 months after leaving the hospital.

“These are often serious infections that require another hospitalization,” she said.

Earlier studies from Huang’s group and others confirmed that an aggressive decolonization within the hospital ICU setting reduced the risk of surgical-site infections, and decolonization protocols are now standard in ICU care.

“The success in the ICU led us to ask the question, ‘Where else can decolonization reduce infection risk?'” Huang said.

The primary outcome in the current trial was MRSA infection as defined by CDC criteria. Secondary outcomes included MRSA infection determined on the basis of clinical judgment, infection from any cause, and infection-related hospitalization.

Analyses were performed using proportional-hazards models in the per-protocol population (all participants who underwent randomization met the inclusion criteria and survived beyond the recruitment hospitalization) and as-treated population (participants stratified according to adherence).

The researchers estimated the number needed to treat in the newly published trial to be 25 to 30 to prevent one infection and hospitalization.

The authors reported that the risk of MRSA infection was significantly lower in the decolonization group compared with the education group (hazard ratio 0.70, 95% CI 0.52-0.96, P=0.03; number needed to treat to prevent one infection 30, 95% CI 18-230). This lower hazard led to a lower risk of hospitalization due to MRSA infection (HR 0.71, 95% CI 0.51-0.99).

The decolonization group had lower likelihoods of clinically judged infection from any cause (HR 0.83, 95% CI 0.70-0.99) and infection-related hospitalization (HR 0.76, 95% CI 0.62-0.93).

In the as-treated analyses, participants in the decolonization group who adhered fully to the regimen had 44% fewer MRSA infections than the education group (HR 0.56, 95% CI 0.36-0.86) and had 40% fewer infections from any cause (HR 0.60, 95% CI 0.46-0.78).

Mild side effects involving antibiotic bathing were reported by around 2% of patients, and 1% each reported mild side effects to the antiseptic mouthwash and nasal ointment.

Although the researchers have not yet completed a cost analysis, Huang said the decolonization intervention, which costs around $150 to $200 over 6 months, should prove to be highly cost effective.

Study limitations included the unblinded intervention — although outcomes were assessed in a blinded fashion – and the substantial attrition over the 1-year follow-up. Also, “adherence was based on reports by the participants, with spot checks of remaining product, both of which may not reflect actual use,” the authors noted.

It is estimated that around 1.8 million MRSA carriers are discharged from hospitals each year.

“That represents about 5% of hospitalized patients, and we have shown that around one in 10 of these will get infected, and end up back in the hospital,” Huang said. “For patients whose risk for infection is high, it is terrific news that there is now a proven topical strategy that can lower that risk.”

The study was funded by the Agency for Health Research and Quality (AHRQ).

Huang disclosed support from the AHRQ Healthcare-Associated Infections Program and the University of California Irvine Institute for Clinical and Translational Science, and relevant relationships with Stryker (Sage Products), Mölnlycke, 3M, Clorox, Xttrium Laboratories, and Medline. Co-authors disclosed multiple relevant relationships with industry.