Patient Safety and Quality

More vigilance in disinfecting hospital surfaces is critical for reducing vancomycin-resistant infections

Hospitalized patients can become infected with a type of intestinal bacteria (enterococci) that is resistant to the broad-spectrum antibiotic vancomycin, which kills a broad range of bacteria. Vancomycin-resistant enterococci (VRE) are now the third leading cause of hospital-acquired infection. More vigilance in disinfecting hospital rooms and surfaces is clearly warranted, concludes a new study.

A Tufts University team obtained weekly environmental and twice-weekly patient surveillance cultures from two intensive care units (ICUs) during a 14-month period. They defined VRE infection as a positive culture result over 48 hours after hospital admission and determined risk factors for VRE infection.

Of 1,330 ICU admissions, 638 patients were at risk for VRE infection, and 50 patients (8 percent) became infected with VRE. Colonization pressure (measure of exposure to VRE in the ICU) and use of multiple antibiotic classes increased risk of VRE infection. However, after adjusting for these factors, the strongest predictors of VRE infection were a prior positive room culture for VRE and prior room occupancy by patients infected with VRE (a presumed proxy for room contamination), which increased risk of VRE infection from 2.7 to 4.4 times. This effect persisted for as long as 2 weeks, when at least one and possibly multiple "terminal cleanings" had occurred. Even if all VRE transmission comes from hospital workers, disinfecting hospital surfaces is likely to reduce transmission, given the frequency of environmental contamination that can subsequently contaminate health care workers' hands.

Environmental cultures may be a useful tool for facilities to monitor the effectiveness of room disinfection procedures or in specific circumstances, such as outbreak control. However, the data do not support routine environmental cultures as an infection control intervention. The study was supported in part by the Agency for Healthcare Research and Quality (T32 HS00060).

See "Prior environmental contamination increases the risk of acquisition of vancomycin-resistant enterococci," by Marci Drees, David R. Snydman, M.D., Christopher H. Schmid, Ph.D., and others, in the March 1, 2008, Clinical Infectious Disease Journal 46, pp. 678-685.

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