Study: At-home decolonization cuts MRSA, other infections

Chlorhexidine mouthwash
Chlorhexidine mouthwash

Decolonization included chlorhexidine mouthwash., John Loo / Flickr cc

The results of a randomized, controlled clinical trial involving patients colonized with methicillin-resistant Staphylococcus aureus (MRSA) indicate a twice-monthly decolonization routine after discharge could significantly reduce the risk of MRSA and other types of bacterial infection.

In a study yesterday in the New England Journal of Medicine, researchers from the University of California Irvine (UCI) School of Medicine and elsewhere reported that, when compared with patients who received only education about MRSA, patients who received education and underwent decolonization cut their MRSA rates substantially.

The patients received the decolonization regimen every other week for 6 months after discharge and had a 30% lower risk of subsequent MRSA infection, a lower risk of infection from any cause, and a lower risk of infection-related hospitalization. The results were even better among those who fully adhered to the regimen.

The results suggest the decolonization strategy may help reduce the burden of MRSA infection among the 5% of hospital inpatients (1.8 million) who carry the pathogen home with them on their skin or in their nose after they leave the hospital. The risk of infection with MRSA, which causes more than 80,000 invasive infections a year in the United States, some severe, is higher among colonized patients who are discharged.

"Currently, patients who have MRSA somewhere on their body have a 1 in 4 risk of developing a serious infection in the year after discharge, and 1 in 10 will develop a new MRSA infection," lead study author Susan Huang, MD, MPH, a professor of in the division of infectious disease at UCI School of Medicine, said in a university press release. "Nearly all of these infections will require re-hospitalization. We have found a way to help prevent them."

Reduced risk of infection, hospitalization

The Project CLEAR (Changing Lives by Eradicating Antibiotic Resistance) trial involved 2,121 adult patients from hospitals and nursing homes in Southern California who had a positive culture test for MRSA. The patients were enrolled 1:1 into an education group, which received an educational binder about MRSA and recommendations for personal hygiene, laundry, and household cleaning after leaving the hospital, and a group that received the educational binder plus decolonization.

The decolonization regimen, which patients were instructed to follow for 5 days a week  twice per month over 6 months, involved the use of 4% rinse-off chlorhexidine for bathing or showering, 0.12% chlorhexidine mouthwash twice daily, and a nasal swab containing 2% mupirocin for twice daily cleaning of the nostrils. All products were provided free to the participants.

The patients were followed up for 12 months after leaving the hospital, with in-person visits occurring at months 1, 3, 6, and 9. The primary outcome was MRSA infection according to Centers for Disease Control and Prevention (CDC) criteria, and secondary outcomes included infection from any cause and infection-related hospitalization.

In the per-protocol population, MRSA infection occurred in 98 of 1,063 patients enrolled in the education group (9.2%) and in 67 of 1,058 enrolled in the education plus decolonization group (6.3%). Across both of these groups, 84.8% of the MRSA infections resulted in hospitalization, with pneumonia and skin- and other soft-tissue infections commonly reported. MRSA bloodstream infections occurred in 28.5% of the infected patients. Infection from any cause occurred in 23.7% of patients (252 of 1,063) in the education group and 19.6% of patients (207 of 1,058) in the education plus decolonization group.

The main unadjusted analysis showed that the risk of MRSA infection was 30% lower in the education plus decolonization group (hazard ratio [HR], 0.70; 95% confidence interval [CI], 0.52 to 0.96, P = 0.03) and the risk of infection from any cause was 17% lower (HR, 0.83; 95% CI, 0.70 to 0.99).

The risk of hospitalization for CDC-defined MRSA was 29% lower (HR, 0.71; 95% CI, 0.51 to 0.99) and 24% lower for any infection-related hospitalization (HR, 0.76; 95% CI, 0.62 to 0.93) among the patients in the education plus decolonization group. The results of the adjusted analyses were similar.

When the investigators assessed the effect of adherence to the decolonization routine, they found that the patients who adhered fully to the regimen were 44% less likely to develop a MRSA infection than patients in the education group (HR, 0.56; 95% CI, 0.36 to 0.86) and 40% less likely to develop any type of infection (HR, 0.60; 95% CI, 0.46 to 0.78).

Overall, the estimated numbers needed to treat to prevent one MRSA infection and one MRSA-related hospitalization were 30 (95% CI, 18 to 230) and 34 (95% CI, 20 to 336), respectively. Among patients who fully adhered to the decolonization regimen, the numbers need to treat to prevent a MRSA infection and associated hospitalization were 26 (95% CI, 18 to 83) and 27 (95% CI, 20 to 46).

Adverse events occurred in 44 of the patients who underwent decolonization, but they mostly involved minor skin irritation.

Characteristics of full adherence

Huang and her colleagues note that participants who fully adhered to the regimen had fewer co-existing conditions, fewer devices, required less bathing assistance, and were more likely to have MRSA infection (rather than colonization) at the time of enrollment than either patients in the education group or those in the education plus decolonization group with lower adherence.

"These differences represent an important practical distinction," the authors write. "To the extent that physicians can identify patients who are able to adhere to an intervention, those patients would derive greater benefit from the recommendation to decolonize."

Limitations of the study include substantial attrition over the 12-month follow up (36%) and use of participant reports to gauge adherence. In addition, the authors note that while resistance to chlorhexidine and mupirocin did not emerge during the trial, it can develop over longer periods of use.

See also:

Feb 14 N Engl J Med abstract

Feb 13 UCI news release

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