Clinical Observation
March 28, 2011

Environmental Cleaning Intervention and Risk of Acquiring Multidrug-Resistant Organisms From Prior Room Occupants

Author Affiliations

Author Affiliations: Division of Infectious Diseases and Health Policy Research Institute, University of California Irvine School of Medicine, Irvine (Mr Datta and Dr Huang); Channing Laboratory, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts (Drs Platt, Yokoe, and Huang).


Copyright 2011 American Medical Association. All Rights Reserved. Applicable FARS/DFARS Restrictions Apply to Government Use.2011

Arch Intern Med. 2011;171(6):491-494. doi:10.1001/archinternmed.2011.64

Background  Admission to intensive care unit rooms previously occupied by carriers of methicillin-resistant Staphylococcus aureus (MRSA) or vancomycin-resistant enteroccoci (VRE) had been found to confer a 40% increased risk of acquisition, presumably through environmental contamination. Subsequently, a cleaning intervention was shown to reduce MRSA and VRE room contamination. We now evaluate the effect of this intervention on the risk of acquiring MRSA and VRE from prior room occupants.

Methods  We conducted a retrospective cohort study of patients admitted to 10 intensive care units at a 750-bed academic medical center during the enhanced cleaning intervention (from September 1, 2006, through April 30, 2008; n = 9449) vs baseline (from September 1, 2003, through April 30, 2005; n = 8203) periods. The intervention consisted of targeted feedback using a black-light marker, cleaning cloths saturated with disinfectant via bucket immersion, and increased education regarding the importance of repeated bucket immersion during cleaning. Intensive care units included medical, cardiac, burn/trauma, general surgery, cardiac surgery, thoracic surgery, and neurosurgery units. We calculated the number of room stays involving the potential for MRSA and VRE acquisition and then assessed the frequency at which eligible patients were exposed to rooms in which the prior occupants had MRSA-positive or VRE-positive status.

Results  Acquisition of MRSA and VRE was lowered from 3.0% to 1.5% for MRSA and from 3.0% to 2.2% for VRE (P < .001 for both). Patients in rooms previously occupied by MRSA carriers had an increased risk of acquisition during the baseline (3.9% vs 2.9%, P = .03) but not the intervention (1.5% vs 1.5%, P = .79) period. In contrast, patients in rooms previously occupied by VRE carriers had an increased risk of acquisition during the baseline (4.5% vs 2.8%, P = .001) and intervention (3.5% vs 2.0%, P < .001) periods.

Conclusions  Enhanced intensive care unit cleaning using the intervention methods may reduce MRSA and VRE transmission. It may also eliminate the risk of MRSA acquisition due to an MRSA-positive prior room occupant.