Decolonization to Reduce Postdischarge Infection Risk among MRSA Carriers

Abstract

Background: Hospitalized patients who are colonized with methicillin-resistant Staphylococcus aureus (MRSA) are at high risk for infection after discharge.

Methods: We conducted a multicenter, randomized, controlled trial of postdischarge hygiene education, as compared with education plus decolonization, in patients colonized with MRSA (carriers). Decolonization involved chlorhexidine mouthwash, baths or showers with chlorhexidine, and nasal mupirocin for 5 days twice per month for 6 months. Participants were followed for 1 year. The primary outcome was MRSA infection as defined according to Centers for Disease Control and Prevention (CDC) criteria. Secondary outcomes included MRSA infection determined on the basis of clinical judgment, infection from any cause, and infection-related hospitalization. All analyses were performed with the use of 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).

Results: In the per-protocol population, MRSA infection occurred in 98 of 1063 participants (9.2%) in the education group and in 67 of 1058 (6.3%) in the decolonization group; 84.8% of the MRSA infections led to hospitalization. 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. The hazard of MRSA infection was significantly lower in the decolonization group than in the education group (hazard ratio, 0.70; 95% confidence interval [CI], 0.52 to 0.96; P=0.03; number needed to treat to prevent one infection, 30; 95% CI, 18 to 230); this lower hazard led to a lower risk of hospitalization due to MRSA infection (hazard ratio, 0.71; 95% CI, 0.51 to 0.99). The decolonization group had lower likelihoods of clinically judged infection from any cause (hazard ratio, 0.83; 95% CI, 0.70 to 0.99) and infection-related hospitalization (hazard ratio, 0.76; 95% CI, 0.62 to 0.93); treatment effects for secondary outcomes should be interpreted with caution owing to a lack of prespecified adjustment for multiple comparisons. In as-treated analyses, participants in the decolonization group who adhered fully to the regimen had 44% fewer MRSA infections than the education group (hazard ratio, 0.56; 95% CI, 0.36 to 0.86) and had 40% fewer infections from any cause (hazard ratio, 0.60; 95% CI, 0.46 to 0.78). Side effects (all mild) occurred in 4.2% of the participants.

Conclusions: Postdischarge MRSA decolonization with chlorhexidine and mupirocin led to a 30% lower risk of MRSA infection than education alone. (Funded by the AHRQ Healthcare-Associated Infections Program and others; ClinicalTrials.gov number, NCT01209234 .).

Figure 1.. Randomization and Follow-up of the Participants.

This flow chart describes the recruitment and the four follow-up visits (at 1, 3, 6, and 9 months) for the 1-year period after hospital discharge. Recruitment occurred during hospitalization, and 19 participants were excluded from the postdischarge trial population because they did not meet inclusion criteria, leaving 2121 participants in the per-protocol population (1063 participants in the education group and 1058 in the decolonization group). Early exit from the trial was provided between each visit and included active withdrawal from the trial, loss to follow-up, and death. Active withdrawal represented situations in which participants indicated their desire to withdraw from the trial. Loss to follow-up was defined as the inability to contact the participant for 3 months, at which point the participant was removed from the trial at the time of last contact. Visits indicate both participants who successfully completed the visit and those who remained in the trial but missed that visit. The mean (±SD) time in the trial (in days) is shown for each group. All deaths were considered by the investigators to be unrelated to side effects from decolonization products. Summary boxes are provided at the bottom of the figure. MRSA denotes methicillin-resistant Staphylococcus aureus.

Figure 2.. Kaplan–Meier Curves for Freedom from MRSA Infection and Infection from Any Cause, Assessed According to CDC Criteria.

Cases of MRSA infection and infection from any cause were assessed according to criteria of the Centers for Disease Control and Prevention come) was significantly greater in the decolonization group than in the education group. The curves remained separated even though decolonizatio stopped at 6 months. Details regarding the numbers of patients at risk for infection and those with infection at the specific time points are provided in Table S7 in the Supplementary Appendix.