Scalable, effective, and rapid decontamination of SARS-CoV-2 contaminated N95 respirators using germicidal ultraviolet C (UVC) irradiation device.

Particulate respirators such as N95s are an essential component of personal protective equipment (PPE) for front-line workers. This study describes a rapid and effective UVC irradiation system that would facilitate the safe re-use of N95 respirators and provides supporting information for deploying UVC for decontamination of SARS-CoV-2 during the COVID-19 pandemic. To assess the inactivation potential of the proposed UVC germicidal device as a function of time by using 3 M 8211-N95 particulate respirators inoculated with SARS-CoV-2. A germicidal UVC device to deliver tailored UVC dose was developed and test coupons (2.5 cm2) of the 3 M-N95 respirator were inoculated with 106 plaque-forming units (PFU) of SARS-CoV-2 and were UV irradiated. Different exposure times were tested (0-164 s) by fixing the distance between the lamp and the test coupon to 15.2 cm while providing an exposure of at least 5.43 mWcm-2. Primary measure of outcome was titration of infectious virus recovered from virus-inoculated respirator test coupons after UVC exposure. Other measures included the method validation of the irradiation protocol, using lentiviruses (biosafety level-2 agent) and establishment of the germicidal UVC exposure protocol. An average of 4.38 × 103 PFU ml-1 (SD 772.68) was recovered from untreated test coupons while 4.44 × 102 PFU ml-1 (SD 203.67), 4.00 × 102 PFU ml-1 (SD 115.47), 1.56 × 102 PFU ml-1 (SD 76.98) and 4.44 × 101 PFU ml-1 (SD 76.98) was recovered in exposures 2, 6, 18 and 54 s per side respectively. The germicidal device output and positioning was monitored and a minimum output of 5.43 mW cm-2 was maintained. Infectious SARS-CoV-2 was not detected by plaque assays (minimal level of detection is 67 PFU ml-1) on N95 respirator test coupons when irradiated for 120 s per side or longer suggesting 3.5 log reduction in 240 s of irradiation, 1.3 J cm-2. A scalable germicidal UVC device to deliver tailored UVC dose for rapid decontamination of SARS-CoV-2 was developed. UVC germicidal irradiation of N95 test coupons inoculated with SARS-CoV-2 for 120 s per side resulted in 3.5 log reduction of virus. These data support the reuse of N95 particle-filtrate apparatus upon irradiation with UVC and supports use of UVC-based decontamination of SARS-CoV-2 during the COVID-19 pandemic.

Practical considerations for Ultraviolet-C radiation mediated decontamination of N95 respirator against SARS-CoV-2 virus.

Decontaminating N95 respirators for reuse could mitigate shortages during the COVID-19 pandemic. Although the United States Center for Disease Control has identified Ultraviolet-C irradiation as one of the most promising methods for N95 decontamination, very few studies have evaluated the efficacy of Ultraviolet-C for SARS-CoV-2 inactivation. In addition, most decontamination studies are performed using mask coupons that do not recapitulate the complexity of whole masks. We sought to directly evaluate the efficacy of Ultraviolet-C mediated inactivation of SARS-CoV-2 on N95 respirators. To that end we created a portable UV-C light-emitting diode disinfection chamber and tested decontamination of SARS-CoV-2 at different sites on two models of N95 respirator. We found that decontamination efficacy depends on mask model, material and location of the contamination on the mask. Our results emphasize the need for caution when interpreting efficacy data of UV-C decontamination methods.

Systematic review on use, cost and clinical efficacy of automated decontamination devices.

BACKGROUND: More evidence is emerging on the role of surface decontamination for reducing hospital-acquired infection (HAI). Timely and adequate removal of environmental pathogens leads to measurable clinical benefit in both routine and outbreak situations. OBJECTIVES: This systematic review aimed to evaluate published studies describing the effect of automated technologies delivering hydrogen peroxide (H202) or ultra-violet (UV) light on HAI rates. METHODS: A systematic review was performed using relevant search terms. Databases were scanned from January 2005 to March 2020 for studies reporting clinical outcome after use of automated devices on healthcare surfaces. Information collected included device type, overall findings; hospital and ward data; study location, length and size; antimicrobial consumption; domestic monitoring; and infection control interventions. Study sponsorship and duplicate publications were also noted. RESULTS: While there are clear benefits from non-touch devices in vitro, we found insufficient objective assessment of patient outcome due to the before-and-after nature of 36 of 43 (84%) studies. Of 43 studies, 20 (47%) used hydrogen peroxide (14 for outbreaks) and 23 (53%) used UV technology (none for outbreaks). The most popular pathogen targeted, either alone or in combination with others, was Clostridium difficile (27 of 43 studies: 63%), followed by methicillin-resistant Staphylococcus aureus (MRSA) (16 of 43: 37%). Many owed funding and/or personnel to industry sponsorship (28 of 43: 65%) and most were confounded by concurrent infection control, antimicrobial stewardship and/or cleaning audit initiatives. Few contained data on device costs and rarely on comparable costs (1 of 43: 2%). There were expected relationships between the country hosting the study and location of device companies. None mentioned the potential for environmental damage, including effects on microbial survivors. CONCLUSION: There were mixed results for patient benefit from this review of automated devices using H202 or UV for surface decontamination. Most non-outbreak studies lacked an appropriate control group and were potentially compromised by industry sponsorship. Concern over HAI encourages delivery of powerful disinfectants for eliminating pathogens without appreciating toxicity or cost benefit. Routine use of these devices requires justification from standardized and controlled studies to understand how best to manage contaminated healthcare environments.

UV-C tower for point-of-care decontamination of filtering facepiece respirators.

BACKGROUND: Filtering facepiece respirators (FFR) are critical for protecting essential personnel and limiting the spread of disease. Due to the current COVID-19 pandemic, FFR supplies are dwindling in many health systems, necessitating re-use of potentially contaminated FFR. Multiple decontamination solutions have been developed to meet this pressing need, including systems designed for bulk decontamination of FFR using vaporous hydrogen peroxide or ultraviolet-C (UV-C) radiation. However, the large scale on which these devices operate may not be logistically practical for small or rural health care settings or for ad hoc use at points-of-care. METHODS: Here, we present the Synchronous UV Decontamination System, a novel device for rapidly deployable, point-of-care decontamination using UV-C germicidal irradiation. We designed a compact, easy-to-use device capable of delivering over 2 J cm2 of UV-C radiation in one minute. RESULTS: We experimentally tested Synchronous UV Decontamination System' microbicidal capacity and found that it eliminates near all virus from the surface of tested FFRs, with less efficacy against pathogens embedded in the inner layers of the masks. CONCLUSIONS: This short decontamination time should enable care-providers to incorporate decontamination of FFR into a normal donning and doffing routine following patient encounters.

Ultraviolet germicidal irradiation of the inner bore of a CT gantry.

PURPOSE: To investigate the feasibility and practicality of ultraviolet (UV) germicidal irradiation of the inner bore of a computed tomography (CT) gantry as a means of viral decontamination. METHOD: A UV lamp (PADNUT 38 W, 253 nm UV-C light tube) and UV-C dosimeter (GENERAL UV-C Digital Light Meter No. UV512C) were used to measure irradiance throughout the inner bore of a CT scanner gantry. Irradiance (units µW/cm2 ) was related to the time required to achieve 6-log viral kill (10-6 survival fraction). RESULTS: A warm-up time of ~120 s was required for the lamp to reach stable irradiance. Irradiance at the scan plane (z = 0 cm) of the CT scanner was 580.9 µW/cm2 , reducing to ~350 µW/cm2 at z = ±20 cm toward the front or back of the gantry. The angular distribution of irradiation was uniform within 10% coefficient of variation. A conservative estimate suggests at least 6-log kill (survival fraction ≤ 10-6 ) of viral RNA within ±20 cm of the scan plane with an irradiation time of 120 s from cold start. More conservatively, running the lamp for 180 s (3 min) or 300 s (5 min) from cold start is estimated to yield survival fraction <<10-7 survival fraction within ±20 cm of the scan plane. CONCLUSION: Ultraviolet irradiation of the inner bore of the CT gantry can be achieved with a simple UV-C lamp attached to the CT couch. Such practice could augment manual wipe-down procedures, improve safety for CT technologists or housekeeping staff, and could potentially reduce turnover time between scanning sessions.

Microwave-Generated Steam Decontamination of N95 Respirators Utilizing Universally Accessible Materials.

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has caused a severe, international shortage of N95 respirators, which are essential to protect health care providers from infection. Given the contemporary limitations of the supply chain, it is imperative to identify effective means of decontaminating, reusing, and thereby conserving N95 respirator stockpiles. To be effective, decontamination must result in sterilization of the N95 respirator without impairment of respirator filtration or user fit. Although numerous methods of N95 decontamination exist, none are universally accessible. In this work, we describe a microwave-generated steam decontamination protocol for N95 respirators for use in health care systems of all sizes, geographies, and means. Using widely available glass containers, mesh from commercial produce bags, a rubber band, and a 1,100-W commercially available microwave, we constructed an effective, standardized, and reproducible means of decontaminating N95 respirators. Employing this methodology against MS2 phage, a highly conservative surrogate for SARS-CoV-2 contamination, we report an average 6-log10 plaque-forming unit (PFU) (99.9999%) and a minimum 5-log10 PFU (99.999%) reduction after a single 3-min microwave treatment. Notably, quantified respirator fit and function were preserved, even after 20 sequential cycles of microwave steam decontamination. This method provides a valuable means of effective decontamination and reuse of N95 respirators by frontline providers facing urgent need.IMPORTANCE Due to the rapid spread of coronavirus disease 2019 (COVID-19), there is an increasing shortage of protective gear necessary to keep health care providers safe from infection. As of 9 April 2020, the CDC reported 9,282 cumulative cases of COVID-19 among U.S. health care workers (CDC COVID-19 Response Team, MMWR Morb Mortal Wkly Rep 69:477-481, 2020, https://doi.org/10.15585/mmwr.mm6915e6). N95 respirators are recommended by the CDC as the ideal method of protection from COVID-19. Although N95 respirators are traditionally single use, the shortages have necessitated the need for reuse. Effective methods of N95 decontamination that do not affect the fit or filtration ability of N95 respirators are essential. Numerous methods of N95 decontamination exist; however, none are universally accessible. In this study, we describe an effective, standardized, and reproducible means of decontaminating N95 respirators using widely available materials. The N95 decontamination method described in this work will provide a valuable resource for hospitals, health care centers, and outpatient practices that are experiencing increasing shortages of N95 respirators due to the COVID-19 pandemic.

The Effect of Brush Motion and Rinsing When Manually Cleaning Cannulated Medical Devices.

Cleaning cannulated medical devices can be challenging for perioperative and sterile processing department personnel. We performed a laboratory experimental study to evaluate differences in cleaning effectiveness using either a back-and-forth or helical spinning brushing motion and the effect of rinsing the bristles at each reintroduction of the brush in the lumen. We also tested the lumen cleanliness after high-pressure water cleansing without brushing. We inspected the devices to determine whether visible soil remained, and we measured the amount of residual organic matter using adenosine triphosphate testing to determine cleaning method effectiveness. The results showed that rinsing the brush during cleaning decreased the amount of organic material that remained in the lumen. A helical spinning motion with brush rinsing at each reintroduction of the brush may be more effective than back-and-forth brushing with rinsing, but additional testing with a larger sample size is required to determine whether this result is replicable.

The effectiveness of germicidal wipes and ultraviolet irradiation in reducing bacterial loads on electronic tablet devices used to obtain patient information in orthopaedic clinics: evaluation of tablet cleaning methods.

BACKGROUND: Electronic tablet devices are commonly used in outpatient clinics to obtain patient information for both clinical and research purposes. These devices are often colonized with bacteria; there are many cleaning methods to reduce this bacterial load. AIM: The primary purpose of this study was to evaluate whether regular cleaning with either germicidal wipes or ultraviolet (UV) irradiation leads to lower bacterial levels compared with irregular cleaning. METHODS: A randomized blinded trial was conducted of tablet cleaning strategies between each patient encounter in orthopaedic clinics. The cleaning method was randomized to either germicidal wipes, UV irradiation, or cleaning only when the tablet was visibly soiled. Research assistants (blinded to the treatment) obtained bacterial cultures from the tablets at the beginning and end of each clinic day. FINDINGS: Using germicidal wipes between each patient encounter vs no routine cleaning resulted in a marked decrease in the amount of bacterial contamination (risk ratio (RR) = 0.17 (0.04-0.67)). Similarly, using UV irradiation between each patient encounter led to significantly lower bacterial contamination rates (RR = 0.29 (95% confidence interval (CI) = 0.09-0.95)) compared with no routine cleaning. The majority of bacteria identified were normal skin flora. No meticillin-resistant Staphylococcus aureus was identified and only sparse colonies of meticillin-sensitive S. aureus. CONCLUSION: Electronic tablets used in orthopaedic trauma clinics are colonized with bacteria if no routine cleaning is performed. Routine use of either UV irradiation or germicidal wipes significantly decreases this bacterial burden. Providers should implement routine cleaning of tablets between each patient encounter to minimize exposure to potential pathogens.

Efficacy of a novel ultraviolet light-emitting diode device for decontamination of shared pens in a health care setting.

Shared pens and styluses are a potential source for transmission of health care-associated pathogens and respiratory viruses in health care facilities. A novel ultraviolet light-emitting diode device was effective in reducing bacteria and viruses inoculated on pens and in reducing methicillin-resistant Staphylococcus aureus transferred to pens by colonized patients. The device could be useful in reducing the risk of transmission of pathogens by shared writing utensils.

The presence of fecal test soil protects bacteria during cleaning/disinfection.

Reusable medical devices (RMDs) must be reprocessed between uses to render them safe for each use and each patient. Cleaning used devices removes organic and inorganic soil making them either safe for reuse or ready for disinfection/sterilization depending on the device. Although cleaning is an important step in a RMD's life cycle, it is not always a priority during device design. In addition, when performing cleaning validation, it is recommended that the manufacturer takes into consideration, what the most appropriate or worst case conditions are in terms of type of soil or the presence of bacteria. This study compared the ability of three different cleaning/disinfecting agents (water, alcohol, and bleach) to remove bacteria and fecal test soil from two different polymers: polypropylene and ultrahigh molecular weight polyethylene (UHMWPE) with two different roughness. There were some differences in the effects of the cleaning/disinfecting agents, the materials, and the roughness depending on the particular circumstances. However, the most consistent effect on the removal of bacteria was the presence of soil, which protected the bacteria from being removed. Conversely, the presence of bacteria played little role in the removal of soil. Although the interactions between material type and roughness, soil type, and bacteria are complicated, they should be taken into account during device design and reprocessing validation to create a device that is easy and safe to use. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 1706-1710, 2019.

Reducing health care-associated infections by implementing separated environmental cleaning management measures by using disposable wipes of four colors.

Background: Environmental cleaning is a fundamental principle of infection control in health care settings. We determined whether implementing separated environmental cleaning management measures in MICU reduced the density of HAI. Methods: We performed a 4-month prospective cohort intervention study between August and December 2013, at the MICU of Cathay General hospital. We arranged a training program for all the cleaning staff regarding separated environmental cleaning management measures by using disposable wipes of four colors to clean the patients' bedside areas, areas at a high risk of contamination, paperwork areas, and public areas. Fifteen high-touch surfaces were selected for cleanliness evaluation by using the adenosine triphosphate (ATP) bioluminescence test. Then data regarding HAI densities in the MICU were collected during the baseline, intervention, and late periods. Results: A total of 120 ATP readings were obtained. The total number of clean high-touch surfaces increased from 13% to 53%, whereas that of unclean high-touch surface decreased from 47% to 20%. The densities of HAI were 14.32‰ and 14.90‰ during the baseline and intervention periods, respectively. The HAI density did not decrease after the intervention period, but it decreased to 9.07‰ during the late period. Conclusion: Implementing separated environmental cleaning management measures by using disposable wipes of four colors effectively improves cleanliness in MICU environments. However, no decrease in HAI density was observed within the study period. Considering that achieving high levels of hand-hygiene adherence is difficult, improving environmental cleaning is a crucial adjunctive measure for reducing the incidence of HAIs.

Pre and post intervention study of antiblastic drugs contamination surface levels at a Pharmacy Department Compounding Area using a closed system drug transfer device and a decontamination process.

Assuring healthcare workers security on Hazardous Drugs (HD) compounding is critical in healthcare settings. Our study aims to demonstrate that the use of a Close System drug Transfer Device (CSTD) PhaSeal™ added to a decontamination process reduces antiblastic surface contamination levels in the Compounding Area (CA) of our Pharmacy Department (PD). We selected cyclophosphamide, 5-fluorouracil and iphosphamide to be evaluated. Testing was carried out with a wipe kit and quantified by an independent laboratory. We defined four sampling times: baseline; just after a decontamination procedure, which was repeated weekly during the study; four months after introduction of CSTD PhaSeal™ for cyclophosphamide and 5-fluorouracil compounding; and after eight months using CSTD PhaSeal™ for cyclophosphamide and 5-fluorouracil and one month for iphosphamide compounding. There was a decrease at the number of positive samples at the beginning/end of the study for all the drugs tested: 28/15 for cyclophosphide, 29/23 for iphosphamide and 7/1 for 5-fluorouracile. Comparing to the baseline, median cyclophosphamide levels significantly decreased (p-value <0.001) at 4 and 8 months sampling time (baseline: 1.01 ng/cm2 to 0.06 ng/cm2 and 0.01 ng/cm2), and median iphosphamide levels significantly decreased (p < 0.001) at 8 months sampling time (baseline: 3.02 ng/cm2 to 0.06 ng/cm2). 5-Fluorouracil did not show significant differences between the sampling times (baseline: 0.09 ng/cm2 to 0.09 ng/cm2). We saw a significant increase at iphosphamide levels at 4 months sampling point, contrary to cyclophosphamide, which levels had decreased. The use of CSTD PhaSeal™ for iphosphamide compounding the last month was implemented for ethical reasons after this intermediate results review. Our study suggests that the use of CSTD PhaSeal™, adding to decontaminating procedures, significantly reduces antiblastic drug surface levels at the CA of our PD.

Decontamination and survival of Enterobacteriaceae on shredded iceberg lettuce during storage.

Enterobacteriaceae family can contaminate fresh produce at any stage of production either at pre-harvest or post-harvest stages. The objectives of the current study were to i) identify Enterobacteriaceae species on iceberg lettuce, ii) compare the decontamination efficiency of water, sodium hypochlorite (free chlorine 200 ppm), peroxyacetic acid (PA 80 ppm; Kenocid 2100®) or their combinations and ionizing radiation against Enterobacteriaceae on shredded iceberg lettuce and iii) determine the survival of Enterobacteriaceae post-treatment storage of shredded iceberg lettuce at 4, 10 and 25 °C, for up to 7 days. Klebsiella pneumonia spp. pneumonia, Enterobacter cloacae, Klebsiella oxytoca, Pantoea spp., Leclercia adecarboxylata and Kluyvera ascorbate were identified on iceberg lettuce. No significant difference (P≥ 0.05) among Enterobacteriaceae survival after washing with water or sanitizing with sodium hypochlorite or Kenocid 2100® (reduction ≤ 0.6 log CFU/g) were found. Combined sanitizer treatments were more effective against Enterobacteriaceae than single washing/sanitizing treatments. Sanitization of iceberg lettuce with combined washing/sanitizing treatments reduced Enterobacteriaceae by 0.85-2.24 CFU/g. Post-treatment growth of Enterobacteriaceae during storage on samples sanitized with sodium hypochlorite and Kenocid 2100® was more than on samples washed with water. The D10-value of Enterobacteriaceae on shredded iceberg lettuce was 0.21 KGy. The reduction of Enterobacteriaceae populations on iceberg after gamma radiation (0.6 KGy) was 3 log CFU/g, however, Enterobacteriaceae counts increased post-irradiation storage by 4-5 log CFU/g. Therefore, washing shredded iceberg lettuce with combined sanitizing treatment (sodium hypochlorite/sodium hypochlorite, sodium hypochlorite/Kenocid 2100®, or Kenocid 2100®/Kenocid 2100®) for total time of 6 min or exposing it to gamma irradiation (0.6 KGy) can decrease the risk of Enterobacteriaceae (reduction ≥ 2 log). Post-washing storage of sliced iceberg lettuce (4, 10, 25 °C) could increase the risk of Enterobacteriaceae as their counts increased during storage even at low temperatures.

Manual Operated Ultraviolet Surface Decontamination for Healthcare Environments.

OBJECTIVE: The aim of this study was to evaluate the effectiveness of a new handheld equipment based on a mercury low-pressure vapor lamp. The Surface UV® device was tested in Staphylococcus aureus, Streptococcus mutans, Streptococcus pneumoniae, two strains of Escherichia coli, Pseudomonas aeruginosa, Candida albicans, and other clinical microorganisms isolated from different surfaces of a public health hospital. BACKGROUND DATA: The incidence of hospital infections has increased in recent years. Despite the variety of available chemicals to reduce the microorganisms, the search for antimicrobial agents and the characterization of novel targets are a continued need. Also, the minimization of chemical procedures is a constant need, and the use of ultraviolet (UV) light as a germicidal device for microorganisms' inactivation has been an alternative and one possible approach for the reduction of contamination. MATERIALS AND METHODS: The in vitro decontamination was performed by application of Surface UV in different species of microorganisms (study 1). The surface decontamination was carried out by application of Surface UV on each surface of hospital environment (study 2). The device presents ultraviolet C (UV-C) light at 254 nm and produces an irradiance of 13 mW/cm2 at a distance of 1 cm of the surfaces. The light dose was 0.78 J/cm2 for 60 sec of application in both studies. RESULTS: The results for in vitro decontamination indicated a log10 reduction factor of 6.5 for S. aureus, 6.7 for S. mutans, 6.2 for S. pneumoniae, 5.4 for E. coli, 5.2 for E. coli (ATCC 8739), 5.4 for P. aeruginosa, and 6.7 for C. albicans. The hospital level of microorganisms decreases more by 75% after the procedure. CONCLUSIONS: The study highlights the development and successful application of a new portable device that can reduce the risk of contamination in health settings. Our results suggest that Surface UV is efficient and may be an alternative decontamination method.

Microbiological interactions with cold plasma.

There is a diverse range of microbiological challenges facing the food, healthcare and clinical sectors. The increasing and pervasive resistance to broad-spectrum antibiotics and health-related concerns with many biocidal agents drives research for novel and complementary antimicrobial approaches. Biofilms display increased mechanical and antimicrobial stability and are the subject of extensive research. Cold plasmas (CP) have rapidly evolved as a technology for microbial decontamination, wound healing and cancer treatment, owing to the chemical and bio-active radicals generated known collectively as reactive oxygen and nitrogen species. This review outlines the basics of CP technology and discusses the interactions with a range of microbiological targets. Advances in mechanistic insights are presented and applications to food and clinical issues are discussed. The possibility of tailoring CP to control specific microbiological challenges is apparent. This review focuses on microbiological issues in relation to food- and healthcare-associated human infections, the role of CP in their elimination and the current status of plasma mechanisms of action.

New Proof-of-Concept in Viral Inactivation: Virucidal Efficacy of 405 nm Light Against Feline Calicivirus as a Model for Norovirus Decontamination.

The requirement for novel decontamination technologies for use in hospitals is ever present. One such system uses 405 nm visible light to inactivate microorganisms via ROS-generated oxidative damage. Although effective for bacterial and fungal inactivation, little is known about the virucidal effects of 405 nm light. Norovirus (NoV) gastroenteritis outbreaks often occur in the clinical setting, and this study was designed to investigate potential inactivation effects of 405 nm light on the NoV surrogate, feline calicivirus (FCV). FCV was exposed to 405 nm light whilst suspended in minimal and organically-rich media to establish the virucidal efficacy and the effect biologically-relevant material may play in viral susceptibility. Antiviral activity was successfully demonstrated with a 4 Log10 (99.99%) reduction in infectivity when suspended in minimal media evident after a dose of 2.8 kJ cm-2. FCV exposed in artificial faeces, artificial saliva, blood plasma and other organically rich media exhibited an equivalent level of inactivation using between 50-85% less dose of the light, indicating enhanced inactivation when the virus is present in organically-rich biologically-relevant media. Further research in this area could aid in the development of 405 nm light technology for effective NoV decontamination within the hospital environment.

Evaluating the effectiveness of ultraviolet-C lamps for reducing keyboard contamination in the intensive care unit: A longitudinal analysis.

BACKGROUND: Ultraviolet (UV) spectrum light for decontamination of patient care areas is an effective way to reduce transmission of infectious pathogens. Our purpose was to investigate the efficacy of an automated UV-C device to eliminate bioburden on hospital computer keyboards. METHODS: The study took place at an academic hospital in Chicago, Illinois. Baseline cultures were obtained from keyboards in intensive care units. Automated UV-C lamps were installed over keyboards and mice of those computers. The lamps were tested at varying cycle lengths to determine shortest effective cycles. Delay after use and prior to cycle initiation was varied to minimize cycle interruptions. Finally, 218 postinstallation samples were analyzed. RESULTS: Of 203 baseline samples, 193 (95.1%) were positive for bacteria, with a median of 120 colony forming units (CFU) per keyboard. There were numerous bacteria linked to health care-associated infections (HAIs), including Staphylococcus, Streptococcus, Enterococcus, Pseudomonas, Pasteurella, Klebsiella, Acinetobacter, and Enterobacter. Of the 193 keyboards, 25 (12.3%) had gram-negative species. Of 218 postinstallation samples, 205 (94%) were sterile. Of the 13 that showed bacterial growth, 6 produced a single CFU. Comparison of pre- and post-UV decontamination median CFU values (120 and 0, respectively) revealed a >99% reduction in bacteria. CONCLUSIONS: The UV lamp effectively decontaminates keyboards with minimal interruption and low UV exposure. Further studies are required to determine reduction of HAI transmission with use of these devices.

Decontamination of indoor air to reduce the risk of airborne infections: Studies on survival and inactivation of airborne pathogens using an aerobiology chamber.

BACKGROUND: Although indoor air can spread many pathogens, information on the airborne survival and inactivation of such pathogens remains sparse. METHODS: Staphylococcus aureus and Klebsiella pneumoniae were nebulized separately into an aerobiology chamber (24.0 m3). The chamber's relative humidity and air temperature were at 50% ± 5% and 20°C ± 2°C, respectively. The air was sampled with a slit-to-agar sampler. Between tests, filtered air purged the chamber of any residual airborne microbes. RESULTS: The challenge in the air varied between 4.2 log10 colony forming units (CFU)/m3 and 5.0 log10 CFU/m3, sufficient to show a ≥3 log10 (≥99.9%) reduction in microbial viability in air over a given contact time by the technologies tested. The rates of biologic decay of S aureus and K pneumoniae were 0.0064 ± 0.00015 and 0.0244 ± 0.009 log10 CFU/m3/min, respectively. Three commercial devices, with ultraviolet light and HEPA (high-efficiency particulate air) filtration, met the product efficacy criterion in 45-210 minutes; these rates were statistically significant compared with the corresponding rates of biologic decay of the bacteria. One device was also tested with repeated challenges with aerosolized S aureus to simulate ongoing fluctuations in indoor air quality; it could reduce each such recontamination to an undetectable level in approximately 40 minutes. CONCLUSIONS: The setup described is suitable for work with all major classes of pathogens and also complies with the U.S. Environmental Protection Agency's guidelines (2012) for testing air decontamination technologies.

'No touch' technologies for environmental decontamination: focus on ultraviolet devices and hydrogen peroxide systems.

PURPOSE OF REVIEW: This article reviews 'no touch' methods for disinfection of the contaminated surface environment of hospitalized patients' rooms. The focus is on studies that assessed the effectiveness of ultraviolet (UV) light devices, hydrogen peroxide systems, and self-disinfecting surfaces to reduce healthcare-associated infections (HAIs). RECENT FINDINGS: The contaminated surface environment in hospitals plays an important role in the transmission of several key nosocomial pathogens including methicillin-resistant Staphylococcus aureus, vancomycin-resistant Enterococcus spp., Clostridium difficile, Acinetobacter spp., and norovirus. Multiple clinical trials have now demonstrated the effectiveness of UV light devices and hydrogen peroxide systems to reduce HAIs. A limited number of studies have suggested that 'self-disinfecting' surfaces may also decrease HAIs. SUMMARY: Many studies have demonstrated that terminal cleaning and disinfection with germicides is often inadequate and leaves environmental surfaces contaminated with important nosocomial pathogens. 'No touch' methods of room decontamination (i.e., UV devices and hydrogen peroxide systems) have been demonstrated to reduce key nosocomial pathogens on inoculated test surfaces and on environmental surfaces in actual patient rooms. Further UV devices and hydrogen peroxide systems have been demonstrated to reduce HAI. A validated 'no touch' device or system should be used for terminal room disinfection following discharge of patients on contact precautions. The use of a 'self-disinfecting' surface to reduce HAI has not been convincingly demonstrated.