SAN DIEGO – A portable device that emits UV-C light destroyed vancomycin-resistant enterococci, Acinetobacter, and C. difficile from hospital rooms where patients infected with those bacteria had been housed, results from a small study demonstrated.
"There is growing evidence that the environment can be a source for acquisition of bad bugs," lead study investigator Dr. Deverick J. Anderson said in an interview prior to IDWeek 2012, where the research was presented during a poster session.
"Our study further strengthens the data that no-touch systems like UV-C light kill important bacteria and can potentially help with current cleaning strategies. While several groups have demonstrated that UV-C light work in experimental conditions we are demonstrating that it works in a real-world hospital environment."
Dr. Anderson of the department of medicine in the division of infectious diseases at Duke University, Durham, N.C., and his associates analyzed 39 rooms at two tertiary care hospitals that had just housed a patient with one of the different bad bugs: vancomycin-resistant enterococci (VRE), Acinetobacter, and C. difficile. After the patient was discharged but prior to the regular cleaning, the investigators obtained 15 or more cultures from several different locations in the hospital rooms, including bed rails, remote controls, and toilets. Then they wheeled in the TRU-D, an automated mobile disinfection system manufactured by Lumalier that is about 6 feet tall and is equipped with 8 sensors and 16 bulbs that emit UV-C light.*
"Each room was irradiated between 25 and 45 minutes in order to eradicate both bacteria and bacterial spores," Dr. Anderson explained during a premeeting telephone press conference. "We then went back into the rooms and cultured the environment from the same locations."
After comparing the number of colony-forming units (CFUs) before and after irradiation "we were able to demonstrate that we could achieve well over 90% reduction in each of those three bad bugs after using the UV light," said Dr. Anderson, who also chairs the antimicrobial stewardship and evaluation team at Duke University Medical Center. "This occurred in all locations sampled, in both direct and indirect light."
Specifically, the UV-C irradiation reduced CFUs of VRE by 98%, C. difficile by 93%, and Acinetobacter by 98%.
"Based on these results we came to the conclusion that UV-C light is indeed effective in killing VRE, C. difficile, and Acinetobacter from the real-world hospital environment," Dr. Anderson said during the telephone press conference. "The idea behind achieving bacterial irradiation in shadow is actually taking advantage of the reflective properties of UV light. It literally bounces around the room and ends up hitting areas in shadow. That’s how bacterial reduction occurs."
He acknowledged certain limitations of the study, including the fact that the researchers were only able to evaluate two hospital rooms with Acinetobacter "because of how infrequently this organism causes infections. Regardless, we reduced the amount of Acinetobacter in both of those rooms."
The study was sponsored by the Centers for Disease Control and Prevention. Lumalier donated the machines used in the study but had no role in the trial design or in review of the data. Dr. Anderson said that he had no relevant financial conflicts to disclose.
IDWeek 2012 is the combined annual meetings of the Infectious Diseases Society of America, the Society for Healthcare Epidemiology of America, the HIV Medicine Association, and the Pediatric Infectious Diseases Society.
CORRECTION 10/18/12: This sentence was amended to state the correct number of sensors and bulbs that emit UV-C light.