Ultraviolet Disinfection Cuts Hospital-Acquired Infections

Mary Beth Nierengarten

May 29, 2014

Use of an ultraviolet environmental disinfection (UVD) system after routine discharge cleaning of contact precautions rooms and other high-risk areas was associated with decreased rates of hospital-acquired infections caused by multidrug-resistant organisms (MDRO) or Clostridium difficile (CD), investigators report in a study published in the June issue of the American Journal of Infection Control.

Supplemental methods currently available for environmental disinfection of patient care environments include UVD technology that uses either mercury bulb devices or pulsed xenon bulb devices. Prior data indicate that both mercury and pulsed xenon bulb devices reduce bacteria, but data are limited on the feasibility of using UVD technology in a healthcare environment and the effect on patient outcomes.

In this retrospective study, Janet P. Haas, PhD, RN, from the Westchester Medical Center Department of Infection Prevention and Control, Valhalla, New York, and colleagues describe implementation of a pulsed xenon UVD system after discharge cleaning of contact precautions rooms and other high-risk areas at a 643-bed tertiary care hospital. The researchers looked at rates of hospital-acquired MDROs and CD before (January 2009 - June 2011) and during (July 2011 - April 2013) UVD use.

Before UVD use, adult patient rooms were disinfected daily and at discharge, using a standard cleaning protocol with sodium hypochlorite; pediatric patient rooms were disinfected using a quaternary ammonium compound. During the period of UVD use, the UVD system was added to this cleaning regimen.

UVD was performed 11,389 times during the study period. Of the UVDs performed, 34% were for contact precautions discharges, 32% were based on staff request, 17% were for routine operating room and burn unit disinfection, and 17% were for disinfection of bathrooms in occupied rooms. Overall, UVD added an average of 51 minutes per discharge.

Overall rates of hospital-acquired MDROs and CD were stable during the period before use of the UVD system (Ptrend = .89) and during the period of UVD use (Ptrend = .28).

However, the rates of hospital-acquired MDRO and CD were significantly lower during UVD use compared with during the period before UVD use (2.14 vs 2.76 cases per 1000 patient days; rate ratio, 0.80; 95% confidence interval, 0.73 - 0.88; P < .001).

The 20% drop in the rates of hospital-acquired MDRO and CD during UVD use were seen despite the fact that 24% of opportunities for UVD of contact precautions rooms at discharge were missed. Miscellaneous reasons accounted for most of the missed use of UVD on discharge (67%), followed by the presence of a roommate (18%), miscommunication with nursing (11%), lack of available machine (3%), and urgent need for room (<1%).

According to the investigators, a decrease in VRE led the overall decreases in MDRO and CD found in the study during the UVD period and accounted for the lowest incidence rates of VRE at their institution for the last decade.

"Although there were many other simultaneous infection control interventions occurring at our hospital during the period from 2009 until 2013 that could have contributed to the reduction in VRE acquisition," state the investigators, "the rates experienced during UVD are the lowest incidence rates of VRE at our institution for the past 10 years and were sustained for 22 months."

Limitations of the study include the fact that the study is from a single institution, the lack of assessment of antibiotic use, and the potential for a cumulative effect of multiple infection control interventions used to reduce acquisition of MDRO and CD.

Am J Infect Control. 2014;42:586-590. Full text


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