Seeing the light on room disinfection

Published: 27-Apr-2011

As healthcare acquired infections continue to plague hospitals, national governments are raising funds to advance the development of new technologies that will beat the bugs. Susan Birks reports on some recent initiatives on both sides of the Atlantic and at studies involving UV hospital disinfection systems

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As healthcare acquired infections continue to plague hospitals, national governments are raising funds to advance the development of new technologies that will beat the bugs. Susan Birks reports on some recent initiatives on both sides of the Atlantic and at studies involving UV hospital disinfection systems.

With the emergence of drug-resistant infections and new pathogens in healthcare settings, new strategies to detect and reduce healthcare associated infections (HAIs) are ever more critical. In the US, the Centers for Disease Control (CDC) estimates that 1 out of 20 hospitalised patients will acquire an infection while receiving healthcare treatment. For this reason the CDC is awarding US$10m for new research to five academic medical centres as part of its Prevention Epicenter grant programme, which supports the development of innovative approaches to reducing HAIs.

Among the innovative strategies that will be explored is the use of combinations of bleach and ultraviolet (UV) light to clean hospital rooms to help prevent infection.

On the other side of the Atlantic, the UK offers a more general Health Innovation Challenge Fund, worth £100m over five years starting from 2010/11. Jointly financed and administered by the Wellcome Trust and the Department of Health, the fund will support development of innovative technologies, devices and clinical procedures. The Scottish government, meanwhile, has tripled its funding to tackle HAIs to more than £50m over three years.

While much of the money will be spent on training and monitoring healthcare staff hand hygiene practices, new disinfection technology is desperately needed as many studies have shown that inadequate terminal cleaning of rooms occupied by patients with multi-drug resistant (MDR) pathogens places the next patient in these rooms at increased risk of acquiring these organisms.

Various room disinfection technologies are coming to the fore, including ‘fogging’ and ‘misting’ using hydrogen peroxide vapour, led by companies such as Bioquell, Integrated Disinfection Technology, Steris, ASP and Zimek, to name just a few. The technology is proving very effective but it requires the room to be vacated for a period of time while the hydrogen peroxide fog or mist dissipates and the surfaces dry.

UV-based disinfection technology, on the other hand, does not require the use of liquids or vapours, and such technologies are now making progress.

Funded studies

Earlier this year an award of $2m was made to Duke University Prevention Epicenter to study the reduction of HAIs using Tru-D, an automated, no-touch UV germicidal device, marketed by Lumalier Corporation in the US. This device is claimed to provide fast, consistent high level disinfection without chemicals, and with minimal training.

Several (unpublished) studies have already focused on the use of Tru-D to control microbial contamination and the manufacturer says all the results show a meaningful reduction of Methicillin-resistant Staphylococcus aureus (MRSA), Vancomycin-resistant Enterococci (VRE), Acinetobacter and C. difficile on an array of environmental surfaces.

At the Fifth Decennial International Conference on Healthcare-Associated Infection, held in Atlanta, US, in April last year, several presentations highlighted the benefit of UV light decontamination (UVLD). Dr William Rutala (UNC Health Care System) gave a presentation in which he said that before-and-after culture tests revealed that automated UV germicidal irradiation reduced >99.9% of vegetative bacteria, 99.84% for C. difficile.

In MRSA patient rooms, UV-C caused a significant reduction in samples positive for MRSA (37 pre versus 2 post) and in total average CFUs (384 pre versus 19 post). The presentation concluded that UV germicidal energy provides “reliable biological activity against a wide range of pathogens”.

According to a presentation on environmental-surface study by Nancy L. Havill, MT, and John M. Boyce, MD (Hospital of Saint Raphael, New Haven, CT), disks inoculated with C. difficile spores (~105) were placed in patient rooms and bathrooms. UV light decontamination (UVLD) reduced the number of C. difficile spores on disks by an average of 99%. Cultures were also obtained from high-touch surfaces in each room before and after UVLD.

When UVLD was first carried out in the patient bathroom, followed by a second cycle in the patient room, 88% of 25 contaminated high-touch surfaces yielded no growth. Havill concluded that UV-C light successfully eliminated aerobic bacteria from most high-touch surfaces.

Another presentation, entitled “Evaluation of an automated ultraviolet radiation device for decontamination of healthcare-associated pathogens in hospital rooms and on portable medical equipment”, was given by a research group from the Louis Stokes Cleveland VA Medical Center, Cleveland, Ohio. According to authors Michelle Nerandzic, Jen Cadnum, Michael Pultz and Curtis Donskey, after routine cleaning 18% of sites under the edges of bedside tables were found to be contaminated with MRSA.

After Tru-D disinfection, sites revealed 0% contamination (P <0.001). An average of 3.5 logs of planted S. warneri remained under each bedside table after routine hospital cleaning versus 0.8 logs per site after Tru-D disinfection (P = 0.06). Tru-D disinfection also reduced the frequency of positive C. difficile cultures by 83%. They concluded that “the Tru-D Rapid Room Disinfection device is an efficient environmental disinfection technology that significantly reduces C. difficile and Staphylococcus spp. contamination on commonly touched hospital surfaces. More important, Tru-D reduces contamination levels on surfaces not easily amenable to standard housekeeping disinfection.

Delivering pulsed UV

Another UV disinfection device being marketed in the US has been developed by Xenex Healthcare Services of Austin, Texas. The Xenex PX-UV device – which is about the size of a vacuum cleaner – can be moved to disinfect the immediate patient bed area, the adjoining bathroom and guest sitting area and can disinfect a patient room in less than eight minutes.

The Xenex PX-UV device uses a powerful xenon light bulb that rises from the device once activated. Its pulses of UV light damage the DNA of bacteria and viruses, preventing them from being able to reproduce or mutate. The light kills germs on TV remotes, telephones, ceilings, curtains and other hard-to-disinfect surfaces.

A recently completed study1 at the University of Texas MD Anderson Cancer Center, sponsored by Xenex Healthcare Services and published in Infection Control and Hospital Epidemiology, found the device significantly reduces the number of bacteria, even after housekeeping staff have carried out thorough cleaning.

The study found that the UV device reduced contamination found on 75 surfaces in 12 in-patient rooms and eliminated VRE. It was conducted in a number of patient rooms, including many in MD Anderson’s Stem Cell Transplant Unit – an area that is vital to keep free of multi-drug resistant organisms (MDROs) because of the immuno-compromised patients being treated there.

For the study, MD Anderson incorporated the device into its bed turnover process that begins once a patient is discharged from the hospital. The housekeeper thoroughly cleans the room, wheels the device into the room and remotely turns it on after stepping into the hallway and closing the room door.

When turned on, the unit’s small lamp emits flashes of xenon ultra-violet light like a strobe. The cleaning process takes less than 10 minutes, reaching surfaces that are difficult for a housekeeper to access and where bacteria or pathogens can linger.

Outside laboratory specialists took surface swabs before the housekeeper cleaned the room, after the room was scrubbed down and then again after using the device. With more than 230 samples taken, researchers found the device further reduced contamination even after a thorough room cleaning by the housekeeping staff. According to the study, researchers found significantly lower heterotrophic plate counts (HPC) and VRE after using the device.

Roy Chemaly, associate professor in the Department of Infectious Diseases, Infection Control and Employee Health, who led the study, said: “This study shows that the device can disinfect a room and eliminate or reduce many sources of this pathogen in hospital rooms. What we need to further study, however, is if it can truly reduce the infection acquired from these organisms in patients in our transplant unit.

“The study shows that this device can enhance the good work of a housekeeping staff, but what will make this an exceptional weapon in infection control, is if we ultimately see fewer patients getting sick from hospital-borne infections.”

According to Mark Stibich, chief scientific officer of Xenex and a collaborator on the project, the study showed that the Xenex room disinfection system is 20 times more effective than traditional cleaning methods in killing dangerous pathogens such as VRE in patient rooms and may have the same effect on MRSA and C. difficile.

Wider applications

He adds that in addition to a study looking at infection rates among patients whose rooms have been disinfected with the Xenex device, future research may explore use of the device in the Critical Care Unit or on floors where there may be sudden outbreaks of a particular infection.

The Xenex PX-UV disinfection system, meanwhile, has been adopted by Moses Cone Health System in three of its hospitals in North Carolina to clean rooms where MRSA patients have stayed.

“The new Xenex technology enables our team to provide a more thorough cleaning to every surface in a room, eliminating hard-to-kill organisms such as MRSA in a fraction of the time,” says Dr Mary Jo Cagle, chief quality officer, Moses Cone Health System.

While more evaluation clearly needs to be carried out, UV disinfection devices appear to offer a valuable weapon in the battle for infection control in healthcare facilities.


1. M. Stibich, J. Stachowiak, B.Tanner, M. Berkheiser, L. Moore, I. Raad, R. Chemaly, Infect. Control Hosp. Epidemiol. 2011 Vol 32 (3)

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