ultraviolet-C Device Research Articles

Shining a light on the pathogenicity of health care providers' mobile phones: Use of a novel ultraviolet-C wave disinfection device

Mobile phones are known to carry pathogenic bacteria and viruses on their surfaces, posing a risk to healthcare providers (HCPs) and hospital infection prevention efforts. We utilize an Ultraviolet-C (UV-C) device to provide an effective method for mobile phone disinfection and survey HCPs about infection risk. Environmental swabs were used to culture HCPs' personal mobile phone surfaces. Four cultures were obtained per phone: before and after the UV-C device's 30-second disinfecting cycle, at the beginning and end of a 12-hour shift. Surveys were administered to participants pre- and poststudy. Total bacterial colony forming units were reduced by 90.5% (P = .006) after one UV-C disinfection cycle, and by 99.9% (P = .004) after 2 cycles. Total pathogenic bacterial colony forming units were decreased by 98.2% (P = .038) after one and >99.99% (P = .037) after 2 disinfection cycles. All survey respondents were willing to use the UV-C device daily to weekly, finding it convenient and beneficial. This novel UV-C disinfecting device is effective in reducing pathogenic bacteria on mobile phones. HCPs would frequently use a phone disinfecting device to reduce infection risk. In light of the ongoing coronavirus (COVID-19) pandemic, a standardized approach to phone disinfection may be valuable in preventing healthcare-associated infections.

Ultraviolet-C decontamination of a hospital room: Amount of UV light needed.

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. Disposable indicators and an electronic radiometer were positioned in ten different positions in a burn ICU room. The room was decontaminated using the Tru-D™-UVC device. Colour changes of the disposable indicators and radiometer readings were noted and compared. Experiment was repeated 10 times. The UVC radiation received in different areas varied between 15.9mJ/cm2 and 1068mJ/cm2 (median 266mJ/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. 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.

Perceptions of Patients, Health Care Workers, and Environmental Services Staff Regarding Ultraviolet Light Room Decontamination Devices

Mobile ultraviolet C (UV-C) room decontamination devices are widely used in health care facilities; however, there is limited information on the perceptions of patients, health care workers (HCWs), and environmental services staff (EVS-staff) regarding their use for environmental decontamination. An anonymous questionnaire was administered to participants in 4 medical/surgical units of a tertiary care hospital where UV-C devices were deployed for a 6-month period. Survey questions assessed perceptions regarding the importance of environmental disinfection, effectiveness of UV-C decontamination, willingness to delay hospital admission in order to use UV-C, and safety of UV-C devices. Questionnaires were completed by 102 patients, 130 HCWs, and 47 EVS-staff. All of the HCWs and EVS-staff and 99% of the patients agreed that environmental disinfection is important to reduce the risk of exposure from contaminated surfaces. Ninety-eight percent of the EVS-staff, 89% of the HCWs, and 96% of the patients felt that the use of UV-C as an adjunct to routine cleaning increased confidence that rooms are clean. Ninety-four percent of the EVS-staff, 85% of the HCWs, and 90% of the patients expressed a willingness to delay being admitted to a room in order to have UV-C decontamination completed. Seventy-nine percent of the EVS-staff, 76% of the HCWs, and 86% of the patients had no concerns about the safety of UV-C devices. Patients, HCWs, and EVS-staff agreed that environmental disinfection is important and that UV-C devices are efficacious and safe. Educational tools are needed to allay safety concerns expressed by a minority of HCWs and EVS-staff.

Effect of a shielded continuous ultraviolet-C air disinfection device on reduction of air and surface microbial contamination in a pediatric oncology outpatient care unit

For a clean hospital environment, we evaluated whether ultraviolet-C (UV-C) air disinfection reduces airborne and surface microbial contamination in an outpatient pediatric oncology center. A pre- and post-intervention study compared 6 test locations, where continuous shielded UV-C air disinfection devices were installed, with 10 control locations without UV-C. Pre- and post-intervention air and surface samples were collected for bacterial and fungal cultures. Percent changes in colony forming unit (CFU) counts in the test and control locations were compared. Mean bacterial CFU count per cubic meter air and per surface contact plates decreased by 27% (P = .219) and 37% (P = .01), respectively, in test locations compared to 40% (P = .054) and 30% (P = .006) reductions in control locations. Mean fungal CFU count per cubic meter air and per surface contact plates increased by 14% (P = .156) and 19% (P = .048), respectively, in test locations compared to 24% (P = .409) and 2% (P = .34) increases in control locations. There were no consistent statistically significant differences in the air and surface culture results between test locations where UV-C devices were installed and control locations. The effectiveness of UV-C air disinfection in reducing air and surface microbial contamination in outpatient clinical areas where immunocompromised children are encountered was not proven.

Evaluation of a shoe sole UVC device to reduce pathogen colonization on floors, surfaces and patients

An ultraviolet C (UVC) decontamination device that delivers germicidal UVC radiation to the soles of shoes has become available recently. To demonstrate that shoe soles can be vectors for healthcare-associated infection, and to investigate if a UVC shoe sole decontamination device would decrease this risk effectively. Three bacterial strains (Staphylococcus aureus, Enterococcus faecalis and Escherichia coli) and a non-toxigenic strain of Clostridium difficile were spiked on to standardized rubber-soled shoe soles and then selected at random for UVC exposure or no UVC exposure. Experiments were performed to test the efficacy of the UVC device to decontaminate shoe soles and flooring. E.faecalis was spiked on to shoes to assess colonization of a simulated healthcare environment and patient. The UVC device decreased shoe sole contamination significantly for all tested bacterial species, and decreased floor contamination significantly for all floor types and species tested (P<0.01 for all experiments). The log10 reduction was the highest for E.coli (mean±standard deviation 2.6±0.79), followed by E.faecalis (2.19±0.68), S.aureus (1.74±0.88) and C.difficile (0.42±0.54) (P<0.0001 for all analyses). Exposure of shoe soles to the UVC device decreased contamination significantly (mean log10 reduction 2.79±1.25; P<0.0001). Proportions of samples from furniture, bed and patient dummy samples decreased from 96-100% positive in controls to 5-8% positive in UVC device experiments (P<0.0001 for all analyses). A UVC decontamination device was shown to reduce the colony-forming unit counts of relevant pathogenic organisms from shoe soles with subsequent decreased colonization of floors, healthcare equipment, furniture, beds and a patient dummy.

Efficacy of an automated ultraviolet C device in a shared hospital bathroom.

Toilet flushing can contribute to disease transmission by generating aerosolized bacteria and viruses that can land on nearby surfaces or follow air currents. Aerobic and anaerobic bacterial bioaerosol loads, and bacterial counts on 2 surfaces in a bathroom with a permanently installed, automated ultraviolet C (UVC) irradiation device, were significantly lower than in a comparable bathroom without the UVC device. Permanently installed UVC lights may be a useful supplementary decontamination tool in shared patient bathrooms.

Impact of Room Location on UV-C Irradiance and UV-C Dosage and Antimicrobial Effect Delivered by a Mobile UV-C Light Device

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-03 W/cm2 in direct sight at a distance of 1.3 m (4 ft) from the device but was 1.12E-05 W/cm2 on a horizontal surface in a shaded area 3.3 m (10 ft) from the device (P4 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. Infect Control Hosp Epidemiol 2016;37:667-672.

Effect of Variation in Test Methods on Performance of Ultraviolet-C Radiation Room Decontamination.

To determine the effect of variation in test methods on performance of an ultraviolet-C (UV-C) room decontamination device. Laboratory evaluation. We compared the efficacy of 2 UV-C room decontamination devices with low pressure mercury gas bulbs. For 1 of the devices, we evaluated the effect of variation in spreading of the inoculum, carrier orientation relative to the device, type of organic load, type of carrier, height of carrier, and uninterrupted versus interrupted exposures on measured UV-C killing of methicillin-resistant Staphylococcus aureus and Clostridium difficile spores. The 2 UV-C room decontamination devices achieved similar log10 colony-forming unit reductions in the pathogens with exposure times ranging from 5 to 40 minutes. On steel carriers, spreading of the inoculum over a larger surface area significantly enhanced killing of both pathogens, such that a 10-minute exposure on a 22-mm2 disk resulted in greater than 2 log reduction in C. difficile spores. Orientation of carriers in parallel rather than perpendicular with the UV-C lamps significantly enhanced killing of both pathogens. Different types of organic load also significantly affected measured organism reductions, whereas type of carrier, variation in carrier height, and interrupted exposure cycles did not. Variation in test methods can significantly impact measured reductions in pathogens by UV-C devices during experimental testing. Our findings highlight the need for standardized laboratory methods for testing the efficacy of UV-C devices and for evaluations of the efficacy of short UV-C exposure times in real-world settings.

Postdischarge decontamination of MRSA, VRE, and Clostridium difficile isolation rooms using 2 commercially available automated ultraviolet-C–emitting devices

Two ultraviolet-C (UVC)-emitting devices were evaluated for effectiveness in reducing methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE), and Clostridium difficile (CD). Six surfaces in rooms previously occupied by patients with MRSA, VRE, or CD were cultured before and after cleaning and after UVC disinfection. In a parallel laboratory study, MRSA and VRE suspended in trypticase soy broth were inoculated onto stainless steel carriers in triplicate, placed in challenging room areas, subjected to UVC, and subcultured to detect growth. Sixty-one rooms and 360 surfaces were assessed. Before cleaning, MRSA was found in 34.4%, VRE was found in 29.5%, and CD was found in 31.8% of rooms. Cleaning reduced MRSA-, VRE-, and CD-contaminated rooms to 27.9%, 29.5%, and 22.7%, respectively (not statistically significant). UVC disinfection further reduced MRSA-, VRE-, and CD-contaminated rooms to 3.3% (P = .0003), 4.9% (P = .0003), and 0% (P = .0736), respectively. Surface colony counts (excluding floors) decreased from 88.0 to 19.6 colony forming units (CFU) (P < .0001) after manual cleaning; UVC disinfection further reduced it to 1.3 CFU (P = .0013). In a multivariable model of the carrier study, the odds of detecting growth in broth suspensions after UVC disinfection were 7 times higher with 1 machine (odds ratio, 6.96; 95% confidence interval, 3.79-13.4) for a given organism, surface, and concentration. UVC devices are effective adjuncts to manual cleaning but vary in their ability to disinfect high concentrations of organisms in the presence of protein.

Evaluating the Efficacy of UV Technology in Acute Care

BackgroundEnvironmental surface cleaning is essential for controlling hospital-acquired infections, but manual disinfection alone is not always sufficient to reduce microorganism presence. Automated ultraviolet-C (UV-C) devices can be used to supplement manual disinfection, but the efficacy of these devices has not yet been fully explored. The objective of this study was to evaluate the performance of a UV-C device following manual disinfection in two U.S. hospitals, with a focus on high-touch surfaces, including electronics and vertical surfaces that are incompatible with solution-based disinfection.MethodsSampling was carried out on 28 types of surfaces present in 21 rooms in two hospitals. The total bacterial load was determined by swabbing each surface in triplicate, then plating and incubating on Rodac plates for 48 hours at 37 °C. Each surface was swabbed after manual disinfection but prior to treatment with an automated UV-C device, and then again following UV-C treatment. The data was fit to a general linear model using commercially available statistics software.ResultsConclusionsTreating hospital rooms with an automated UV-C device may be a safe and effective way to reduce or eliminate microorganism presence that remains after manual disinfection, particularly for high-touch or vertical surfaces that are incompatible with solution-based methods. Further clinical studies should generate enough data to assess the impact of UV-C devices on hospital-acquired infection prevention. BackgroundEnvironmental surface cleaning is essential for controlling hospital-acquired infections, but manual disinfection alone is not always sufficient to reduce microorganism presence. Automated ultraviolet-C (UV-C) devices can be used to supplement manual disinfection, but the efficacy of these devices has not yet been fully explored. The objective of this study was to evaluate the performance of a UV-C device following manual disinfection in two U.S. hospitals, with a focus on high-touch surfaces, including electronics and vertical surfaces that are incompatible with solution-based disinfection. Environmental surface cleaning is essential for controlling hospital-acquired infections, but manual disinfection alone is not always sufficient to reduce microorganism presence. Automated ultraviolet-C (UV-C) devices can be used to supplement manual disinfection, but the efficacy of these devices has not yet been fully explored. The objective of this study was to evaluate the performance of a UV-C device following manual disinfection in two U.S. hospitals, with a focus on high-touch surfaces, including electronics and vertical surfaces that are incompatible with solution-based disinfection. MethodsSampling was carried out on 28 types of surfaces present in 21 rooms in two hospitals. The total bacterial load was determined by swabbing each surface in triplicate, then plating and incubating on Rodac plates for 48 hours at 37 °C. Each surface was swabbed after manual disinfection but prior to treatment with an automated UV-C device, and then again following UV-C treatment. The data was fit to a general linear model using commercially available statistics software. Sampling was carried out on 28 types of surfaces present in 21 rooms in two hospitals. The total bacterial load was determined by swabbing each surface in triplicate, then plating and incubating on Rodac plates for 48 hours at 37 °C. Each surface was swabbed after manual disinfection but prior to treatment with an automated UV-C device, and then again following UV-C treatment. The data was fit to a general linear model using commercially available statistics software. Results ConclusionsTreating hospital rooms with an automated UV-C device may be a safe and effective way to reduce or eliminate microorganism presence that remains after manual disinfection, particularly for high-touch or vertical surfaces that are incompatible with solution-based methods. Further clinical studies should generate enough data to assess the impact of UV-C devices on hospital-acquired infection prevention. Treating hospital rooms with an automated UV-C device may be a safe and effective way to reduce or eliminate microorganism presence that remains after manual disinfection, particularly for high-touch or vertical surfaces that are incompatible with solution-based methods. Further clinical studies should generate enough data to assess the impact of UV-C devices on hospital-acquired infection prevention.

Room Decontamination Using an Ultraviolet-C Device with Short Ultraviolet Exposure Time

Room Decontamination Using an Ultraviolet-C Device with Short Ultraviolet Exposure Time