Terminal Cleaning, Including UV Sterilization, Effectiveness in Mitigating Pathogen Transmission

Because more than 2.8 million antibiotic-resistant infections occur in United States hospitals each year resulting in more than 35,000 patient deaths, the study of these infections is high on investigators’ minds. An estimated annual cost nationally to treat these hospital-acquired infections (HAI) that are multidrug-resistant organisms (MDROs) is more than $4.6 billion. In addition, previous research has suggested that a prior room (source) occupant who is an MDRO carrier increases the risk to the subsequent room (exposed) occupant of infection with that MDRO.

One suggested tool to mitigate these MDRO transmissions is the use of UV-C sterilization, but how effective is it?

In a recent retrospective cohort study, investigators assessed hospital-acquired MDRO infection transmission in patients who had been subsequently assigned to a single-patient room of a source occupant who carried 1 or more MDROs on or during admission. In addition, patient acquisition of 5 pathogens was compared between exposed patients in rooms with standard chlorine-based disinfectant terminal cleaning with or without additional UV-C disinfection. The investigators used logistic regression analysis to estimate the adjusted risk of pathogen transfer with added use of UV-C disinfection.

The investigators compared rates of MDRO transmission by UV-C status from January 1, 2016, through December 31, 2018, in acute-care, single patient hospital rooms at 6 hospitals within a 40-hospital academic health care system,The University of Pittsburgh Medical Center (UPMC). During this study period, individual hospitals incorporated UV-C disinfection at different times. To explore possible temporal changes, the outcome was evaluated for each hospital during the 12 months preceding implementation of UV-C disinfection.

“Despite a plausible theoretical basis, studies on the use of UV-C disinfection to reduce the incidence of HAI have been conflicting, inconclusive, or have had methodological shortcomings,” the investigators noted in the study. “[The] cluster-randomized trial provided a nuanced view of the effectiveness of UV-C technology, with a demonstrated reduction in microbial contamination; however, a potential additional benefit of UV-C disinfection was not observed for facilities using chlorine-based cleaning products.A second, smaller, cluster-randomized trial of UV disinfection in 5 inpatient units with immunocompromised patients did not find a reduction in acquisition of vancomycin-resistant Enterococcus (VRE), or Clostridioides difficile (C difficile) when used daily and after patient discharge."

The investigators further explained their process: “We evaluated more definitively the extent to which discretionary (ie, nonrandomized) use of adjunct UV-C disinfection across a large hospital system might reduce the incidence of source occupancy transmission of hospital-acquired pathogens with varying exposure time. We approached this analysis in a 2-sided manner given the possibility that implementation of adjunct UV-C disinfection could potentially influence hospital staff adherence to standard chlorine-based disinfectant terminal room cleaning procedures…Our analysis does not support the use of UV-C in addition to post-discharge cleaning with chlorine-based disinfectant to lower the risk of prior room occupant pathogen transfer.”

For the study, 33,771 exposed patient admissions were evaluated, and the source occupants carried 46,688 unique pathogens for a mean of 1.4 per source occupant. Before the 33,771 patient admissions, 5,802 rooms (17.2%) were treated with UV-C disinfection in addition to standard terminal cleaning procedures. After the investigators adjusted for covariates, the exposed patients in rooms treated with adjunct UV-C disinfection were at comparable risk of transfer of any pathogen (odds ratio, 1.06; 95% CI, 0.84–1.32; P = .64).

Of the pathogens evaluated, MRSA and VRE were most prevalent among the source patients. Interestingly, rooms that underwent UV-C disinfection between source and exposed patients had a significantly longer source-patient admission, exposed-patient admission, and time between admissions, than rooms without UV-C disinfection.

The investigators concluded, “These findings suggest that inadequate terminal (ie, postdischarge) room cleaning may be an environmental source of pathogen transmission…[in addition,] results of our analysis indicate that adjunct UV-C disinfection does not provide incremental value in reducing transfer of MDRO above and beyond standard of care.”

This study “Assessment of the effectiveness of ultraviolet-C disinfection on transmission of hospital-acquired pathogens from prior room occupants,” was recently published in the University of Cambridge Press.