MRSA Decolonization--Clarian Health Partners' Experience

Background: Hospitalized patients colonized with MRSA have been reported to have a 20-25% risk of readmission with serious MRSA disease in the 18 months after discharge.  Our local data confirm these reported findings. 

Objective: We hypothesize that use of topical antibiotic and antiseptic agents to decolonize patients with MRSA may reduce both transmission of MRSA and the colonized patients' own risk of subsequent MRSA disease.

Methods: We prospectively introduced serial interventions first to reduce transmission of MRSA, then to reduce risk of subsequent MRSA disease in MRSA-colonized patients. Patients in the intensive care and progressive care units of two tertiary care teaching hospitals (812-bed and 324-bed) were included.  Intervention timeline:  Phase 1 (Jul 2006 to Jan-Apr 2008)--active MRSA screening of admissions followed by contact isolation of patients identified as MRSA carriers; Phase 2 (Jan-Apr 2008 to Dec 2008)--thrice weekly chlorhexidine (CHG) bathing; Phase 3 (Jan 2009 to Aug-Oct 2009) daily CHG bathing; Phase 4 (Aug-Oct 2009 to present) decolonization with CHG bathing and oral rinse and nasal mupirocin. Outcomes included the MedMined ™ MRSA nosocomial infection marker (NIM) rate and subsequent MRSA disease. A MRSA NIM is a positive MRSA culture (excluding nasal screening) in a hospitalized patient on or after day 3 or within 14 days of discharge.  Duplicate cultures are excluded.  The MRSA NIM rate is (# MRSA NIMs)/# admissions.

Results: The two hospitals had mixed results with the thrice-weekly CHG bathing.  Both hospitals had reduced nosocomial MRSA infection rates after daily CHG bathing was introduced, with further reduction after decolonization.

 

	2008 (MWF CHG bathing added Jan-May 2008)	2009 (daily CHG bathing started Jan 2009)	Jan-Jun 2010 (decolonization started Aug-Oct 2009)
	rate nosocomial MRSA infections (MRSA NIMs)
Methodist ICU	0.0078	0.0061	0.0042
Methodist ICU+PCU	0.0059	0.0048	0.0034
Methodist all inpatient	0.0059	0.0043	0.0037
University ICU	0.0073	0.006	0.0045
University ICU+PCU	0.0048	0.0043	0.0047
University all inpatient	0.0051	0.0051	0.0042

Table 1.  Impact of daily CHG bathing (Jan 2009) and decolonization (Aug-Oct 2009) on rates of nosocomial MRSA, as measured by MedMined ™ MRSA nosocomial infection markers (NIMs), at Methodist and University Hospital.

Of the 937 patients who started the decolonization protocol Aug-Oct 2009 through Jun-Jul 2010, only 646 (69%) completed decolonization therapy.  Interim analysis of the first 492 decolonized patients at Methodist shows only 13 (3%) had subsequent MRSA disease (defined as a positive clinical culture, excluding repeat nasal swabs) at 6-month follow-up.

Conclusions: Decolonization of MRSA carriers, in addition to other infection control measures, may reduce both MRSA transmission in hospitals and subsequent MRSA disease in carriers.  We need longer follow-up to determine whether reduced disease in carriers is sustained or reflects delayed disease onset.