1. Ultraviolet-C decontamination of a hospital room
Marie Lindblad, Eva Tano, Claes Lindahl, Fredrik Huss
Our primary aim was to investigate, using a commercial radiometer, the ultraviolet C (UVC) dose received in different areas in a burn ICU ward room after an automated UVC decontamination. The secondary aim was to validate a disposable UVC-dose indicator with the radiometer readings. Methods: Disposable indicators and an electronic radiometer were positioned in ten different positions in a burn ICU room. The room was decontaminated using the Tru-DTM-UVC device. Colour changes of the disposable indicators and radiometer readings were noted and compared. Experiment was repeated 10 times. Findings: The UVC radiation received in different areas varied between 15.9mJ/cm2 and 1068 mJ/cm2 (median 266 mJ/cm2). Surfaces, at shorter distances and in the direct line of sight of the UVC device showed statistically significant higher UVC doses than surfaces in the shadow of equipment (p = 0.019). The UVC-dose indicator’s colour change corresponded with the commercially radiometer readings. Conclusions: The amount of UVC radiation that is received in surfaces depends on their locations in the room (ie distance from the UVC emitter) and whether any objects shadow the light. In this study we suggest that quality controls should be used to assure that enough UVC radiation reaches all surfaces. © 2019 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-
2. Applications of ultraviolet germicidal irradiation disinfection in health care facilities
Farhad Memarzadeh, Russell N. Olmsted and Judene M. Bartley
This review evaluates the applicability and relative contribution of ultraviolet germicidal irradiation (UVGI) to disinfection of air in health care facilities. A section addressing the use of UVGI for environmental surfaces is also included. The germicidal susceptibility of biologic agents is addressed, but with emphasis on application in health care facilities. The balance of scientific evidence indicates that UVGI should be considered as a disinfection application in a health care setting only in conjunction with other well-established elements, such as appropriate heating, ventilating, and air-conditioning (HVAC) systems; dynamic removal of contaminants from the air; and preventive maintenance in combination with through cleaning of the care environment. We conclude that although UVGI is microbiocidal, it is not ‘‘ready for prime time’’ as a primary intervention to kill or inactivate infectious microorganisms; rather, it should be considered an adjunct. Other factors, such as careful design of the built environment, installation and effective operation of the HVAC system, and a high level of attention to traditional cleaning and disinfection, must be assessed before a health care facility can decide to rely solely on UVGI to meet indoor air quality requirements for health care facilities. More targeted and multiparameter studies are needed to evaluate the efficacy, safety, and incremental benefit of UVGI for mitigating reservoirs of microorganisms and ultimately preventing cross-transmission of pathogens that lead to health care-associated infections.
3. Evaluation of an automated ultraviolet radiation device for decontamination of Clostridium difficile
Michelle M Nerandzic, Jennifer L Cadnum, Michael J. Pultz and Curtis J. Donskey
Background: Environmental surfaces play an important role in transmission of healthcare-associated pathogens. There is a need for new disinfection methods that are effective against Clostridium difficile spores, but also safe, rapid, and automated. Methods: The Tru-DTM Rapid Room Disinfection device is a mobile, fully-automated room decontamination technology that utilizes ultraviolet-C irradiation to kill pathogens. We examined the efficacy of environmental disinfection using the Tru-D device in the laboratory and in rooms of hospitalized patients. Cultures for C. difficile, methicillin-resistant Staphylococcus aureus (MRSA), and vancomycin-resistant Enterococcus (VRE) were collected from commonly touched surfaces before and after use of Tru-D. Results: On inoculated surfaces, application of Tru-D at a reflected dose of 22,000 μWs/cm2 for ~45 minutes consistently reduced recovery of C. difficile spores and MRSA by >2-3 log10 colony forming units (CFU)/cm2 and of VRE 2 by >3-4 log10 CFU/cm . Similar killing of MRSA and VRE was achieved in ~20 minutes at a reflected dose of 12,000 μWs/cm2, but killing of C. difficile spores was reduced. Disinfection of hospital rooms with Tru-D reduced the frequency of positive MRSA and VRE cultures by 93% and of C. difficile cultures by 80%. After routine hospital cleaning of the rooms of MRSA carriers, 18% of sites under the edges of bedside tables (i.e., a frequently touched site not easily amenable to manual application of disinfectant) were contaminated with MRSA, versus 0% after Tru-D (P < 0.001). The system required <5 minutes to set up and did not require continuous monitoring. Conclusions: The Tru-D Rapid Room Disinfection device is a novel, automated, and efficient environmental disinfection technology that significantly reduces C. difficile, VRE and MRSA contamination on commonly touched hospital surfaces.
4. IUVA Fact Sheet on COVID-19
The International Ultraviolet Association (IUVA) believes that UV disinfection technologies can play a role in a multiple barrier approach to reducing the transmission of the virus causing COVID-19, SARS- CoV-2, based on current disinfection data and empirical evidence. UV is a known disinfectant for air, water and surfaces that can help to mitigate the risk of acquiring an infection in contact with the COVID- 19 virus when applied correctly. “The IUVA has assembled leading experts from around the world to develop guidance on the effective use of UV technology, as a disinfection measure, to help reduce the transmission of COVID-19 virus. Established in 1999, the IUVA is a nonprofit dedicated to the advancement of ultraviolet technologies to help address public health and environmental concerns,” says Dr. Ron Hofmann, Professor at the University of Toronto, and President of the IUVA. It must be noted that “UVC”, “UV disinfection” and “UV” as used here and in the scientific, medical and technical literature, specifically and importantly refers to UVC light energy (200-280nm light) in the germicidal range which is not the same as the UVA and UVB used in tanning beds or sunlight exposure.
5. Impact of Room Location on UV-C Irradiance and UV-C Dosage and Antimicrobial Effect Delivered by a Mobile UV-C Light Device
John M. Boyce, Patricia A. Farrel, Dana Towle, Renee Fekieta, Michael Aniskiewicz
Objective: to evaluate ultraviolet C (UV-C) irradiance, UV-C dosage, and antimicrobial effect achieved by a mobile continuous UV-C device. Design: prospective observational study. Methods: we used 6 UV light sensors to determine UV-C irradiance (W/cm2) and UV-C dosage (μWsec/cm2) at various distances from and orientations relative to the UV-C device during 5-minute and 15-minute cycles in an ICU room and a surgical ward room. In both rooms, stainless-steel disks inoculated with methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus (VRE), and Clostridium difficile spores were placed next to sensors, and UV-C dosages and log10 reductions of target organisms achieved during 5-minute and 15-minute cycles were determined. Mean irradiance and dosage readings were compared using ANOVA. Results: mean UV-C irradiance was nearly 1.0E-03W/cm2 in direct sight at a distance of 1.3m (4 ft) from the device but was 1.12E-05W/cm2 on a horizontal surface in a shaded area 3.3 m (10 ft) from the device (P < .001). Mean UV-C dosages received by UV-C sensors located at different distances and orientation relative to the device varied significantly during 5-minute cycles and during 15-minute cycles (P < .001). Log10 reductions ranged from >4 to 1–3 for MRSA, >4 to 1–2 for VRE and >4 to 0 log10 for C. difficile spores, depending on the distance from, and orientation relative to, the device with 5-minute and 15-minute cycles. Conclusion: UV-C irradiance, dosage, and antimicrobial effect received from a mobile UV-C device varied substantially based on location in a room relative to the UV-C device.
6. THEORETICAL MODEL FOR THE UV DISINFECTION SYSTEM IN THE OPERATING WARD OF PZU “FILIP VTORI”
Here we investigate the theoretical modeling of an UV disinfection system for the operating ward in PZU ”FILIP VTORI”. As nocosomial infections pose a serious threat to patients everywhere in the world, here the disinfection of the air and the surfaces is modeled and discussed. The surfaces are disinfected with direct illumination of open UV after hours system, UV curtains, overhead disinfection, floor disinfection and disinfection of the incoming air through the ventilation/air-condition system. From the results it can be seen that the concentrations of bacteria, fungi and viruses drop significantly which in turn should give a significant drop in a number of hospital acquired infections.
7. Portable Ultraviolet Light Surface-Disinfecting Devices for Prevention of Hospital-Acquired Infections
ONTARIO HEALTH TECHNOLOGY ASSESSMENT SERIES
The database search for the clinical review yielded 10 peer-reviewed publications that met eligibility criteria. Three studies focused on mercury UV-C–based technology, seven on pulsed xenon UV technology. Findings were either inconsistent or produced very low-quality evidence using the GRADE rating system. The intervention was effective in reducing the rate of the composite outcome of HAIs (combined) and colonization (but quality of evidence was low). For the review of economic studies, 152 peer-reviewed publications were identified and screened. No studies met the inclusion criteria. Under the assumption that two devices would be purchased per hospital, we estimated the 5-year budget impact of $586,023 for devices that use the pulsed xenon technology and of $634,255 for devices that use the mercury technology.
8. A model for choosing an automated ultraviolet-C disinfection systemand building a case for the C-suite
Maureen Spencer, Michelle Vignari, Elizabeth Bryce, Helen Boehm Johnson, Loretta Fauerbach, Denise Graham
Environmental disinfection has become the new frontier in the ongoing battle to reduce the risk of health care–associated infections. Evidence demonstrating the persistent contamination of environmental sur- faces despite traditional cleaning and disinfection methods has led to the widespread acceptance that there is both a need for reassessing traditional cleaning protocols and for using secondary disinfection technologies. Ultraviolet-C (UV-C) disinfection is one type of no-touch technology shown to be a suc- cessful adjunct to manual cleaning in reducing environmental bioburden. The dilemma for the infection preventionist, however, is how to choose the system best suited for their facility among the many UV-C surface disinfection delivery systems available and how to build a case for acquisition to present to the hospital administration/C-suite. This article proposes an approach to these dilemmas based in part on the experience of 2 health care networks.