Enhanced Cleaning of ICUs Associated With Reduced Risk of MRSA Transmission

An intervention for enhanced cleaning of intensive care unit (ICU) rooms that included increased education on important cleaning techniques was associated with a lower rate of acquisition of methicillin-resistant Staphylococcus aureus (MRSA) in rooms that were previously occupied by MRSA carriers, according to a report in the March 28 issue of Archives of Internal Medicine.

Environmental contamination with multidrug-resistant organisms may facilitate the spread of health care-associated infections. This is particularly important in ICUs, in which patients are at high risk of infection due to comorbidities [co-existing illnesses], wounds, and the use of medical devices. Prior research has shown that admission to an ICU room previously occupied by a patient harboring MRSA or vancomycin-resistant enterococci (VRE) was associated with a 40 percent increased risk of acquisition, according to background information in the article.

Rupak Datta, MPH, of the University of California Irvine School of Medicine, and colleagues conducted a study to assess the effect of a cleaning intervention on the risk of acquiring MRSA and VRE from prior room occupants. The study included patients admitted to ten intensive care units at a 750-bed academic medical center during the enhanced cleaning intervention (from September 2006 through April 2008; n = 9,449) vs. baseline (from September 2003 through April 2005; n = 8,203) periods. An ammonium agent was used for baseline discharge cleaning. The intervention consisted of targeted feedback regarding the adequacy of cleaning using a nontoxic tracking marker whose marks are visible only under UV light ("black-light"); changing the application of disinfectant from pouring from bottles onto cleaning cloths to bucket immersion of cleaning cloths; 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. The researchers 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.

The researchers found that overall, MRSA and VRE acquisition decreased when comparing the intervention period to the baseline period, with MRSA acquisition declining from 3 percent (305 of 10,151) to 1.5 percent (182 of 11,849); and VRE acquisition decreasing from 3 percent (314 of 10,349) to 2.2 percent (256 of 11,871). When evaluating acquisition by prior occupant status, patients in rooms previously occupied by MRSA carriers had an increased risk of acquisition during the baseline (3.9 percent vs. 2.9 percent) but not the intervention (1.5 percent vs. 1.5 percent) period. In contrast, patients in rooms previously occupied by VRE carriers had an increased risk of acquisition during the baseline (4.5 percent vs. 2.8 percent) and intervention (3.5 percent vs. 2 percent) periods, the authors write.

Whereas enhanced ICU cleaning appears to be effective in decreasing MRSA and VRE transmission, it may be more effective in reducing transmission of MRSA compared with VRE," the researchers say. "Reasons for this difference may include the generally higher burden of VRE contamination and evidence that room contamination may be a major factor in VRE transmission.

The researchers conclude, In summary, we show that enhanced ICU cleaning involving targeted feedback using a black-light marker, disinfectant-saturated cleaning cloths, and increased education regarding best-practice cleaning methods may reduce MRSA and VRE transmission and eliminate the risk of MRSA acquisition due to an MRSA-positive prior room occupant. Recent studies have particularly highlighted the black-light marker component of this campaign for its superior role in providing feedback compared with routine visual inspection. However additional studies are needed to evaluate the differential effect of enhanced cleaning on MRSA vs. VRE. This may be particularly relevant for hospitals with high VRE prevalence where the burden of VRE contamination may demand more rigorous cleaning methods."

Reference: Arch Intern Med. 2011;171[6]:491-494.