UV Light Disinfection Reduced Hospital-Wide C. difficile Cases

Deverick J Anderson, MD, MPH

While ultraviolet (UV) light might not have an effect on the current hospitalized patient, the method does have an effect on the next patient to stay in that room and an indirect effect on hospital-acquired infections in the rest of the hospital.

Researchers from Duke University employed the Benefits of Enhanced Terminal Room (BETR) Disinfection study to determine the effectiveness of 4 disinfection strategies throughout 9 hospitals. The research showed that enhanced terminal room disinfection with UV light in a subset of high-risk rooms resulted in a decrease in the risk of acquisition of multidrug-resistant organisms, like C. difficile, for all patients in the hospital.

“These findings are important, because they suggest that strategies targeting high-risk rooms might have benefit for the larger population of patients admitted to hospital by reducing the burden of pathogenic organisms in the hospital microbiome,” wrote the study authors led by Deverick J Anderson, MD, MPH, associate professor of medicine at Duke University Medical Center.

Anderson’s research team wanted to build on that research, employing the BETR study techniques to test the disinfection methods on C. difficile, methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE), and multidrug-resistant Acinetobacter spp. During a period from April 2012 to July 2014, patients were included in the data if they remained in the hospital for at least 48 hours and acquired an infection while at the hospital.

The investigators described 4 strategies: A) a reference, where ammonium or bleach (in the case of C. difficile) was used in the rooms; B) UV disinfection; C) bleach; and D) bleach plus UV light. The sequence of strategies was randomly assigned to each hospital and each strategy was used for 7 months. Overall, there were 271,740 unique patients, with 375,918 hospital admissions. Of those, 314,610 admissions met all inclusion criteria.

There was no significant difference between standard disinfection and the 3 enhanced disinfection strategies in terms of the hospital-wide risk of acquisition for all the multidrug-resistant organisms combined, the researchers determined. They noted, however, that the largest decrease in risk of target organism acquisition was in the UV study period.

They also said the use of bleach in rooms did not significantly decrease risk compared to the standard disinfection strategies. The hospital-wide risk for infection was described as “similar” for the bleach and UV strategy and the reference period.

For C. difficile specifically, the investigators said the hospital-wide risk for infection was significantly lower during the UV study period compared to the reference period (rate 9.13 per 10000 patient days vs 10.1 per 10,000 patient days; RR 0∙89, 95% CI 0.80—0.99; p = 0.031). However, the hospital-wide risk for infection with C. difficile was not significantly lower during the bleach evaluation or the bleach plus UV light observation period.

Patients who stayed in rooms that were cleaned the standard way had a lower incidence of C. difficile infection during UV observation periods than during other tested methods. The researchers reported 729 cases of hospital acquired C. difficile infection during observation periods without UV light, compared to 592 cases when UV light was being used as a disinfectant.

“We believe enhanced terminal room disinfection strategies that target high-risk rooms led to a decrease in hospital-wide incidence of multidrug-resistant organisms and C. difficile through several plausible direct and indirect methods,” the study authors concluded.

However, they continued that while these results might not be significant, they add support to the primary results of the BETR Disinfection study that showed benefits to enhanced terminal room disinfection methods. The study authors also added that UV light used as a disinfectant has a direct effect on the next patient who uses that room, leading to an indirect benefit for other hospitalized patients.

“Enhanced terminal room disinfection using UV is only one piece of the puzzle,” wrote Matthew P. Crotty, PharmD, and Marie H. Wilson, BSN, BS, RN, both of the Methodist Dallas Medical Center, in a comment on the study. “Although UV light might help put a stop to the transmission of epidemiologically important pathogens, continued efforts in coordinating the optimal use of antimicrobials will be crucial for any successes in the ongoing battle to curb antibiotic resistance.”

The paper, “Effectiveness of targeted enhanced terminal room disinfection on hospital-wide acquisition and infection with multidrug-resistant organisms and Clostridium difficile,” was published in The Lancet Infectious Diseases.