scholarly journals Effectiveness of Ultraviolet-C Light and a High-Level Disinfection Cabinet for Decontamination of N95 Respirators

2020 ◽  
Vol 5 (1) ◽  
pp. 52 ◽  
Author(s):  
Jennifer L. Cadnum ◽  
Daniel Li ◽  
Sarah N. Redmond ◽  
Amrita R. John ◽  
Basya Pearlmutter ◽  
...  
Keyword(s):  
Methicillin Resistant Staphylococcus Aureus ◽  
Test Method ◽  
Dry Heat ◽  
Ultraviolet C ◽  
Multiple Cycles ◽  
American Society ◽  
High Level ◽  
N95 Respirators ◽  
Uv C ◽  
Disk Test

Background-Shortages of personal protective equipment (PPE) including N95 filtering facepiece respirators is an urgent concern in the setting of the global COVID-19 pandemic.  Decontamination of PPE could be useful to maintain adequate supplies, but there is uncertainty regarding the efficacy of decontamination technologies.Methods-A modification of the American Society for Testing and Materials standard quantitative carrier disk test method (ASTM E-2197-11) was used to examine the effectiveness of ultraviolet-C (UV-C) light, a high-level disinfection cabinet that generates aerosolized peracetic acid and hydrogen peroxide, and dry heat at 70°C for 30 minutes for decontamination of bacteriophages Phi6 and MS2 and methicillin-resistant Staphylococcus aureus (MRSA) inoculated onto 3 commercial N95 respirators.  Three and 6 log10 reductions on N95 respirators were considered effective for decontamination and disinfection, respectively. Results-UV-C administered as a 1-minute cycle in a UV-C box or a 30-minute cycle by a room decontamination device reduced contamination but did not meet criteria for decontamination of the viruses from all sites for any of the N95s.  The high-level disinfection cabinet was effective for decontamination of all the organisms from the N95s and achieved disinfection with 3 disinfection cycles over ~60 minutes.  Dry heat at 70°C for 30 minutes was not effective for decontamination of the bacteriophages.  Conclusions-UV-C could be useful to reduce contamination on N95 respirators.  However, the UV-C technologies studied did not meet our criteria for decontamination under the test conditions used.  The high-level disinfection cabinet was effective for decontamination of N95s and met criteria for disinfection with multiple cycles.

Efficacy of relatively low-cost ultraviolet-C light devices against Candida auris

2021 ◽  
pp. 1-5
Author(s):  
Basya S. Pearlmutter ◽  
Muhammed F. Haq ◽  
Jennifer L. Cadnum ◽  
Annette L. Jencson ◽  
Matthew Carlisle ◽  
...  
Keyword(s):  
Low Cost ◽  
Test Method ◽  
Clinical Settings ◽  
Candida Auris ◽  
Resource Limited ◽  
Colorimetric Indicator ◽  
Ultraviolet C ◽  
American Society ◽  
Carrier Test ◽  
Uv C

Abstract Background: Ultraviolet-C (UV-C) light devices could be useful to reduce environmental contamination with Candida auris. However, variable susceptibility of C. auris strains to UV-C has been reported, and the high cost of many devices limits their use in resource-limited settings. Objective: To evaluate the efficacy of relatively low-cost (<$15,000 purchase price) UV-C devices against C. auris strains from the 4 major phylogenetic clades. Methods: A modification of the American Society for Testing and Materials (ASTM) standard quantitative disk carrier test method (ASTM E 2197) was used to examine and compare the effectiveness of UV-C devices against C. auris, methicillin-resistant Staphylococcus aureus (MRSA), and bacteriophage Phi6. Reductions of 3 log10 were considered effective. UV-C irradiance measurements and colorimetric indicators were used to assess UV-C output. Results: Of 8 relatively low-cost UV-C devices, 6 met the criteria for effective decontamination of C. auris isolates from clades I and II, MRSA, and bacteriophage Phi6, including 3 room decontamination devices and 3 UV-C box devices. Candida auris isolates from clades III and IV were less susceptible to UV-C than clade I and II isolates; 1 relatively low-cost room decontamination device and 2 enclosed box devices met the criteria for effective decontamination of clade III and IV isolates. UV-C irradiance measurements and colorimetric indicator results were consistent with microorganism reductions. Conclusions: Some relatively low-cost UV-C light technologies are effective against C. auris, including isolates from clades III and IV with reduced UV-C susceptibility. Studies are needed to evaluate the effectiveness of UV-C devices in clinical settings.

scholarly journals Evaluation of Ultraviolet-C Light for Rapid Decontamination of Airport Security Bins in the Era of SARS-CoV-2

2020 ◽  
Vol 5 (1) ◽  
pp. 133 ◽  
Author(s):  
Jennifer Cadnum ◽  
Daniel F. Li ◽  
Lucas D. Jones ◽  
Sarah N. Redmond ◽  
Basya Pearlmutter ◽  
...  
Keyword(s):  
Rna Virus ◽  
Test Method ◽  
Airport Security ◽  
Dna Viruses ◽  
Bacteriophage Ms2 ◽  
Test Organisms ◽  
Ultraviolet C ◽  
American Society ◽  
Uv C ◽  
Rna And Dna

Background:  Contaminated surfaces are a potential source for spread of respiratory viruses including SARS-CoV-2.  Ultraviolet-C (UV-C) light is effective against RNA and DNA viruses and could be useful for decontamination of high-touch fomites that are shared by multiple users. Methods:  A modification of the American Society for Testing and Materials standard quantitative carrier disk test method (ASTM E-2197-11) was used to examine the effectiveness of ultraviolet-C (UV-C) light for rapid decontamination of plastic airport security bins inoculated at 3 sites with methicillin-resistant Staphylococcus aureus (MRSA) and bacteriophages MS2, PhiX174, and Phi6, an enveloped RNA virus used as a surrogate for coronaviruses. Three log10 reductions on inoculated plastic bins were considered effective for decontamination. Results: UV-C light administered as 10-, 20-, or 30-second cycles in proximity to a plastic bin reduced contamination on each of the test sites, including vertical and horizontal surfaces.  The 30-second cycle met criteria for decontamination of all 3 test sites for all the test organisms except bacteriophage MS2 which was reduced by greater than 2 log10 PFU at each site. Conclusions: UV-C light is an attractive technology for rapid decontamination of airport security bins.  Further work is needed to evaluate the utility of UV-C light in real-world settings and to develop methods to provide automated movement of bins through a UV-C decontamination process.

scholarly journals Mapping of UV-C dose and SARS-CoV-2 viral inactivation across N95 respirators during decontamination

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Alisha Geldert ◽  
Alison Su ◽  
Allison W. Roberts ◽  
Guillaume Golovkine ◽  
Samantha M. Grist ◽  
...  
Keyword(s):  
Optical Simulation ◽  
Pathogen Inactivation ◽  
Viral Inactivation ◽  
Flexible Form ◽  
Measurement Tools ◽  
Ultraviolet C ◽  
N95 Respirators ◽  
Uv C ◽  
Dose Difference

AbstractDuring public health crises like the COVID-19 pandemic, ultraviolet-C (UV-C) decontamination of N95 respirators for emergency reuse has been implemented to mitigate shortages. Pathogen photoinactivation efficacy depends critically on UV-C dose, which is distance- and angle-dependent and thus varies substantially across N95 surfaces within a decontamination system. Due to nonuniform and system-dependent UV-C dose distributions, characterizing UV-C dose and resulting pathogen inactivation with sufficient spatial resolution on-N95 is key to designing and validating UV-C decontamination protocols. However, robust quantification of UV-C dose across N95 facepieces presents challenges, as few UV-C measurement tools have sufficient (1) small, flexible form factor, and (2) angular response. To address this gap, we combine optical modeling and quantitative photochromic indicator (PCI) dosimetry with viral inactivation assays to generate high-resolution maps of “on-N95” UV-C dose and concomitant SARS-CoV-2 viral inactivation across N95 facepieces within a commercial decontamination chamber. Using modeling to rapidly identify on-N95 locations of interest, in-situ measurements report a 17.4 ± 5.0-fold dose difference across N95 facepieces in the chamber, yielding 2.9 ± 0.2-log variation in SARS-CoV-2 inactivation. UV-C dose at several on-N95 locations was lower than the lowest-dose locations on the chamber floor, highlighting the importance of on-N95 dose validation. Overall, we integrate optical simulation with in-situ PCI dosimetry to relate UV-C dose and viral inactivation at specific on-N95 locations, establishing a versatile approach to characterize UV-C photoinactivation of pathogens contaminating complex substrates such as N95s.

scholarly journals 1215. Ultraviolet-C (UV-C) Monitoring Made Ridiculously Simple: UV-C Dose Indicators for Convenient Measurement of UV-C Dosing

2019 ◽  
Vol 6 (Supplement_2) ◽  
pp. S437-S437
Author(s):  
Jennifer Cadnum ◽  
Annette Jencson ◽  
Sarah Redmond ◽  
Thriveen Sankar Chittoor Mana ◽  
Curtis Donskey
Keyword(s):  
Methicillin Resistant Staphylococcus Aureus ◽  
Fetal Calf Serum ◽  
Color Change ◽  
Calf Serum ◽  
Organic Load ◽  
Healthcare Facilities ◽  
Log Reduction ◽  
Ultraviolet C ◽  
Effective Doses ◽  
Uv C

Abstract Background Ultraviolet-C (UV-C) light is increasingly used as an adjunct to standard cleaning in healthcare facilities. However, most facilities do not have a means to measure UV-C to determine whether effective doses are being delivered. We tested the efficacy of 2 easy-to-use colorimetric indicators for monitoring UV-C dosing in comparison to log reductions in pathogens. Methods In a laboratory setting, we exposed methicillin-resistant Staphylococcus aureus (MRSA) and Clostridium difficile spores on steel disk carriers with or without an organic load (5% fetal calf serum) to UV-C for varying times resulting in fluence exposures ranging from 10,000 to 100,000 µJ/cm2. The UV-C indicators were placed adjacent to the carriers. Log reductions were calculated in comparison to untreated controls and the change in color of the indicators was correlated with dose and log reductions. Results The UV-C doses required to achieve a 3-log reduction in MRSA and C. difficile were 10,000 and 46,000 µJ/cm2, respectively. For both indicators, there was a visible color change from baseline at 10,000 µJ/cm2 and a definite final color change by 46,000 µJ/cm2 (Figure 1). Organic load had only a modest impact on UV-C efficacy. The indicators required only a few seconds to place and were easy to read (Figure 2). Conclusion UV-C doses of 10,000 and 46,000 µJ/cm2 were required to achieve 3 log reductions of MRSA and C. difficile spores, respectively. The colorimetric indicators provide an easy means to monitor UV-C dosing. Disclosures All authors: No reported disclosures.

Terminal Decontamination of Patient Rooms Using an Automated Mobile UV Light Unit

2011 ◽  
Vol 32 (8) ◽  
pp. 737-742 ◽  
Author(s):  
John M. Boyce ◽  
Nancy L. Havill ◽  
Brent A. Moore
Keyword(s):  
Uv Light ◽  
Patient Discharge ◽  
Test Method ◽  
Cycle Times ◽  
Ozone Concentrations ◽  
Environmental Surfaces ◽  
Before And After ◽  
American Society ◽  
Carrier Test ◽  
Uv C

Objective.To determine the ability of a mobile UV light unit to reduce bacterial contamination of environmental surfaces in patient rooms.Methods.An automated mobile UV light unit that emits UV-C light was placed in 25 patient rooms after patient discharge and operated using a 1- or 2-stage procedure. Aerobic colony counts were calculated for each of 5 standardized high-touch surfaces in the rooms before and after UV light decontamination (UVLD). Clostridium difficile spore log reductions achieved were determined using a modification of the ASTM (American Society for Testing and Materials) International E2197 quantitative disk carrier test method. In-room ozone concentrations during UVLD were measured.Results.For the 1-stage procedure, mean aerobic colony counts for the 5 high-touch surfaces ranged from 10.6 to 98.2 colony-forming units (CFUs) per Dey/Engley (D/E) plate before UVLD and from 0.3 to 24.0 CFUs per D/E plate after UVLD, with significant reductions for all 5 surfaces (all P<.02). Surfaces in direct line of sight were significantly more likely to yield negative culture results after UVLD than before UVLD (all P<.001). Mean C. difficile spore log reductions ranged from 1.8 to 2.9. UVLD cycle times ranged from 34.2 to 100.1 minutes. For the 2-stage procedure, mean aerobic colony counts ranged from 10.0 to 89.2 CFUs per D/E plate before UVLD and were 0 CFUs per D/E plate after UVLD, with significant reductions for all 5 high-touch surfaces. UVLD cycle times ranged from 72.1 to 146.3 minutes. In-room ozone concentrations during UVLD ranged from undetectable to 0.012 ppm.Conclusions.The mobile UV-C light unit significantly reduced aerobic colony counts and C. difficile spores on contaminated surfaces in patient rooms.

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

2020 ◽  
Author(s):  
Guillaume R. Golovkine ◽  
Allison W. Roberts ◽  
Chase Cooper ◽  
Sebastian Riano ◽  
Angela M. DiCiccio ◽  
...  
Keyword(s):  
Light Emitting Diode ◽  
Model Material ◽  
Efficacy Data ◽  
Light Emitting ◽  
Ultraviolet C ◽  
N95 Respirators ◽  
Uv C ◽  
Disinfection Chamber

AbstractDecontaminating N95 respirators for reuse could mitigate shortages during the COVID-19 pandemic. We tested a portable UV-C light-emitting diode disinfection chamber and found that decontamination efficacy depends on mask model, material and location on the mask. This emphasizes the need for caution when interpreting efficacy data of UV-C decontamination methods.

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

PLoS ONE ◽  
2021 ◽  
Vol 16 (10) ◽  
pp. e0258336
Author(s):  
Guillaume R. Golovkine ◽  
Allison W. Roberts ◽  
Chase Cooper ◽  
Sebastian Riano ◽  
Angela M. DiCiccio ◽  
...  
Keyword(s):  
United States ◽  
Light Emitting Diode ◽  
The United States ◽  
Model Material ◽  
Efficacy Data ◽  
Light Emitting ◽  
Ultraviolet C ◽  
N95 Respirators ◽  
Uv C ◽  
Disinfection Chamber

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.

scholarly journals Evaluation of no-touch technologies for decontamination of toys in pediatric healthcare settings

2021 ◽  
Author(s):  
Hanan Haydar ◽  
Jessica A Kumar ◽  
Jennifer L Cadnum ◽  
Emily Zangla ◽  
Claudia K Hoyen ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Methicillin Resistant ◽  
Healthcare Settings ◽  
Clostridioides Difficile ◽  
Bacteriophage Ms2 ◽  
Ultraviolet C ◽  
High Level ◽  
Pediatric Healthcare

Abstract No-touch technologies could be useful to decontaminate shared toys in healthcare settings. A high-level disinfection cSabinet and electrostatic sprayer were effective against methicillin-resistant Staphylococcus aureus (MRSA), bacteriophage MS2, and Clostridioides difficile spores on toys. An ultraviolet-C light box was less effective but reduced MRSA and bacteriophage MS2 by &gt;2 log10.

scholarly journals Evaluation of 2 Ultraviolet-C Light Boxes for Decontamination of N95 Respirators

2021 ◽  
Vol 6 (1) ◽  
pp. 104-115
Author(s):  
Jennifer Cadnum ◽  
Basya Pearlmutter ◽  
Daniel Li ◽  
Annette Jencson ◽  
Jacob Scott ◽  
...  
Keyword(s):  
Limited Information ◽  
Bacterial Strains ◽  
Bacteriophage Ms2 ◽  
Different Types ◽  
Reduction Methods ◽  
Ultraviolet C ◽  
N95 Respirators ◽  
Uv C

Background:  Ultraviolet-C (UV-C) light devices are effective in reducing contamination on N95 filtering facepiece respirators.  However, limited information is available on whether UV-C devices meet the Food and Drug Administration’s (FDA) microbiological requirements for Emergency Use Authorization (EUA) for respirator bioburden reduction.  Methods:  We tested the ability of 2 UV-C light boxes to achieve the 3-log10 microorganism reductions required for EUA for reuse by single users.  Whole 3M 1860 or Moldex 1513 respirators were inoculated on the exterior facepiece, interior facepiece, and internal fibers with bacteriophage MS2 and/or 4 strains of bacteria and treated with UV-C cycles of 1 or 20 minutes.  Colorimetric indicators were used to assess penetration of UV-C through the respirators.    Results:  For 1 UV-C box, a 20-minute treatment achieved the required bioburden reduction for Moldex 1513 but not 3M 1860 respirators.  For the second UV-C box, a 1-minute treatment achieved the required bioburden reduction in 4 bacterial strains for the Moldex 1513 respirator.  Colorimetric indicators demonstrated penetration of UV-C through all layers of the Moldex 1513 respirator but not the 3M 1860 respirator.  Conclusions:  Our findings demonstrate that UV-C box technologies can achieve bioburden reductions required by the FDA for EUA for single users but highlight the potential for variable efficacy for different types of respirators. 

scholarly journals Non-uniform UV-C dose across N95 facepieces can cause 2.9-log variation in SARS-CoV-2 inactivation

2021 ◽  
Author(s):  
Alisha Geldert ◽  
Alison Su ◽  
Allison W. Roberts ◽  
Guillaume Golovkine ◽  
Samantha M. Grist ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Optical Simulation ◽  
Viral Inactivation ◽  
Flexible Form ◽  
Measurement Tools ◽  
Ultraviolet C ◽  
N95 Respirators ◽  
Uv C ◽  
Dose Difference

AbstractDuring public health crises like the COVID-19 pandemic, ultraviolet-C (UV-C) decontamination of N95 respirators for emergency reuse has been implemented to mitigate shortages. However, decontamination efficacy across N95s is poorly understood, due to the dependence on received UV-C dose, which varies across the complex three-dimensional N95 shape. Robust quantification of UV-C dose across N95 facepieces presents challenges, as few UV-C measurement tools have sufficient 1) small, flexible form factor, and 2) angular response. To address this gap, we combine optical modeling and quantitative photochromic indicator (PCI) dosimetry with viral inactivation assays to generate high-resolution maps of “on-N95” UV-C dose and concomitant SARS-CoV-2 viral inactivation across N95 facepieces within a commercial decontamination chamber. Using modeling to rapidly identify on-N95 locations of interest, in-situ measurements report a 17.4 ± 5.0-fold dose difference across N95 facepieces, yielding 2.9 ± 0.2-log variation in SARS-CoV-2 inactivation. UV-C dose at several on-N95 locations was lower than the lowest-dose locations on the chamber floor, highlighting the importance of on-N95 dose validation. Overall, we couple optical simulation with in-situ PCI dosimetry to relate UV-C dose and viral inactivation at specific

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