scholarly journals Disinfection of N95 Respirators with Ozone

2020 ◽  
Author(s):  
Edward P Manning ◽  
Matthew D Stephens ◽  
Sannel Patel ◽  
Sylvie Dufresne ◽  
Bruce Silver ◽  
...  
Keyword(s):  
Ambient Air ◽  
Filtration Efficiency ◽  
Ozone Exposure ◽  
Healthcare Personnel ◽  
First Report ◽  
High Level ◽  
N95 Respirators ◽  
Airtight Chamber ◽  
Ozone Disinfection ◽  
Chamber Exposure

The coronavirus disease 2019 crisis is creating a shortage of personal protective equipment (PPE), most critically, N95 respirators for healthcare personnel. Our group was interested in the feasibility of ozone disinfection of N95 respirators as an alternative for healthcare professionals and organizations that might not have access to other disinfection devices. We tested the effectiveness of ozone on killing Pseudomonas aeruginosa (PsA) on three different N95 respirators: 3M 1860, 3M 1870, and 3M 8000. We used an ozone chamber that consisted of: an airtight chamber, an ozone generator, an ozone destruct unit, and an ozone UV analyzer. The chamber was capable of concentrating ozone up to 500 parts per million (ppm) from ambient air, creating an airtight seal, and precisely measuring ozone levels within the chamber. Exposure to ozone at 400 ppm with 80% humidity for two hours effectively killed bacteria on N95 respirators, types 1860, 1870, and 8000. There were no significant changes in filtration efficiency of the 1860 and 1870 type respirators for up to ten cycles of ozone exposure at similar conditions. There was no change in fit observed in the 1870 type respirator after ozone exposure. There was no significant change in the strap integrity of the 1870 type respirator after ozone exposure. Tests for filtration efficiency were not performed on the 8000 type respirator. Tests for fit or strap integrity were not performed on the 8000 or 1860 type respirators. This study demonstrates that an ozone application achieves a high level of disinfection against PsA, a vegetative bacteria that the CDC identifies as more difficult to kill than medium sized viruses such as SARS-CoV-2 (Covid-19). Furthermore, conditions shown to kill these bacteria did not damage or degrade respirator filtration. This is the first report of successful disinfection of N95 PPE with ozone of which the authors are aware. It is also the first report, to the authors' knowledge, to identify necessary conditions for ozone to kill organisms on N95 masks without degrading the function of N95 filters.

scholarly journals Scalable In-hospital Decontamination of N95 Filtering Facepiece Respirator with a Peracetic Acid Room Disinfection System

2020 ◽  
Author(s):  
Amrita R. John ◽  
Shine Raju ◽  
Jennifer L. Cadnum ◽  
Kipum Lee ◽  
Phillip McClellan ◽  
...  
Keyword(s):  
Peracetic Acid ◽  
Structural Integrity ◽  
Filtration Efficiency ◽  
Material Structure ◽  
Cycle Duration ◽  
Bacteriophage Ms2 ◽  
Large Numbers ◽  
Care Workers ◽  
High Level ◽  
N95 Respirators

AbstractBackgroundCritical shortages of personal protective equipment (PPE) especially N95 respirators, during the SARS-CoV-2 pandemic continues to be a source of great concern among health care workers (HCWs). Novel methods of N95 filtering facepiece respirator (FFR) decontamination that can be scaled-up for in-hospital use can help address this concern and keep HCWs safe.MethodsA multidisciplinary pragmatic study was conducted to evaluate the use of an ultrasonic room high-level disinfection system (HLDS) that generates aerosolized peracetic acid (PAA) and hydrogen peroxide for decontamination of large numbers of N95 respirators. A cycle duration that consistently achieved disinfection of N95 respirators (defined as ≤ 6 log10 reductions in bacteriophage MS2 and Geobacillus stearothermophilus spores inoculated onto respirators) was identified. The treated masks were then assessed for changes to their hydrophobicity, material structure, strap elasticity, and filtration efficiency (FE). Assessment of PAA off-gassing from a treated mask was also performed.ResultsThe PAA room HLDS was effective for disinfection of N95 respirators in a 2447 cubic feet room with deploy and dwell times of 16 and 32 minutes respectively, and a total cycle time of 1 hour and 16 minutes. After 5 treatment cycles, no adverse effects were detected on filtration efficiency, structural integrity, or strap elasticity. There was no detectable off-gassing of PAA from the treated masks.ConclusionThe PAA room disinfection system provides a rapidly scalable solution for in-hospital decontamination of large numbers of N95 respirators to meet the needs of HCWs during the SARS-CoV-2 pandemic.

scholarly journals Invitro filtration efficiency for selected face masks to bacteria with a size smaller than SARS-CoV-2 respiratory droplet

2020 ◽  
Author(s):  
Maryam Amour ◽  
Hussein H. Mwanga ◽  
George M. Bwire
Keyword(s):  
Escherichia Coli ◽  
Double Layer ◽  
Ambient Air ◽  
Filtration Efficiency ◽  
Cotton Cloth ◽  
Colony Forming Units ◽  
Spread Of Infection ◽  
N95 Respirators ◽  
And Control ◽  
Respiratory Droplets

Abstract Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) can be transmitted between people through respiratory droplets (droplet particles are >5-10 μm in diameter). We conducted an invitro experiment to determine the filtration efficiency for selected face masks (cloth and medical face masks and N95 respirators) to bacteria with a size (0.5-1.5 μm in diameter) smaller than SARS-CoV-2 respiratory droplet. Bacteria suspension was prepared using normal saline (NaCl) and bacteria (Staphylococcus aureus and Escherichia coli) and maintained at a turbidity of 0.5 MacFarland. The suspensions was put in a 100ml plastic spray bottle (with an approximated 250 μl and flow rate of 31.5 ft3/min per spray) and then a single spray was performed to the test masks. Swabbing was done to unsprayed side of the test mask within 0 and after 4 hrs. The swab was streaked on CLED media then incubated for 48 hours at 37oC in ambient air. Bacterial filtration efficiency (BFE) was determined as the proportions of colony forming units (CFUs) between the test and control mask. The selected face masks had BFE of 100% and >99% for medical and double layer cotton cloth masks, respectively. This study supports the use of cotton cloth (at least double layer) face coverings in public settings where other social distancing measures are difficult to maintain to prevent the spread of infection from the wearer.

scholarly journals Scalable in-hospital decontamination of N95 filtering face-piece respirator with a peracetic acid room disinfection system

2020 ◽  
pp. 1-10 ◽  
Author(s):  
Amrita R. John ◽  
Shine Raju ◽  
Jennifer L. Cadnum ◽  
Kipum Lee ◽  
Phillip McClellan ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Peracetic Acid ◽  
Structural Integrity ◽  
Filtration Efficiency ◽  
Material Structure ◽  
Cycle Duration ◽  
Bacteriophage Ms2 ◽  
Large Numbers ◽  
High Level ◽  
N95 Respirators

Abstract Background: Critical shortages of personal protective equipment, especially N95 respirators, during the coronavirus disease 2019 (COVID-19) pandemic continues to be a source of concern. Novel methods of N95 filtering face-piece respirator decontamination that can be scaled-up for in-hospital use can help address this concern and keep healthcare workers (HCWs) safe. Methods: A multidisciplinary pragmatic study was conducted to evaluate the use of an ultrasonic room high-level disinfection system (HLDS) that generates aerosolized peracetic acid (PAA) and hydrogen peroxide for decontamination of large numbers of N95 respirators. A cycle duration that consistently achieved disinfection of N95 respirators (defined as ≥6 log10 reductions in bacteriophage MS2 and Geobacillus stearothermophilus spores inoculated onto respirators) was identified. The treated masks were assessed for changes to their hydrophobicity, material structure, strap elasticity, and filtration efficiency. PAA and hydrogen peroxide off-gassing from treated masks were also assessed. Results: The PAA room HLDS was effective for disinfection of bacteriophage MS2 and G. stearothermophilus spores on respirators in a 2,447 cubic-foot (69.6 cubic-meter) room with an aerosol deployment time of 16 minutes and a dwell time of 32 minutes. The total cycle time was 1 hour and 16 minutes. After 5 treatment cycles, no adverse effects were detected on filtration efficiency, structural integrity, or strap elasticity. There was no detectable off-gassing of PAA and hydrogen peroxide from the treated masks at 20 and 60 minutes after the disinfection cycle, respectively. Conclusion: The PAA room disinfection system provides a rapidly scalable solution for in-hospital decontamination of large numbers of N95 respirators during the COVID-19 pandemic.

scholarly journals COVID-19 global pandemic planning: Dry heat incubation and ambient temperature fail to consistently inactivate SARS-CoV-2 on N95 respirators

2020 ◽  
pp. 153537022097781
Author(s):  
Douglas J Perkins ◽  
Robert A Nofchissey ◽  
Chunyan Ye ◽  
Nathan Donart ◽  
Alison Kell ◽  
...  
Keyword(s):  
Ambient Temperature ◽  
Personal Protective Equipment ◽  
Healthcare Personnel ◽  
Protective Equipment ◽  
Experimental Conditions ◽  
Dry Heat ◽  
Global Pandemic ◽  
Individual Site ◽  
Pandemic Planning ◽  
N95 Respirators

The ongoing pandemic of the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has placed a substantial strain on the supply of personal protective equipment, particularly the availability of N95 respirators for frontline healthcare personnel. These shortages have led to the creation of protocols to disinfect and reuse potentially contaminated personal protective equipment. A simple and inexpensive decontamination procedure that does not rely on the use of consumable supplies is dry heat incubation. Although reprocessing with this method has been shown to maintain the integrity of N95 respirators after multiple decontamination procedures, information on the ability of dry heat incubation to inactivate SARS-CoV-2 is largely unreported. Here, we show that dry heat incubation does not consistently inactivate SARS-CoV-2-contaminated N95 respirators, and that variation in experimental conditions can dramatically affect viability of the virus. Furthermore, we show that SARS-CoV-2 can survive on N95 respirators that remain at room temperature for at least five days. Collectively, our findings demonstrate that dry heat incubation procedures and ambient temperature for five days are not viable methods for inactivating SARS-CoV-2 on N95 respirators for potential reuse. We recommend that decontamination procedures being considered for the reuse of N95 respirators be validated at each individual site and that validation of the process must be thoroughly conducted using a defined protocol.

scholarly journals Physicochemical Quality and Microbial Activity of Dairy Milk with Ozonation

2021 ◽  
Vol 16 (2) ◽  
pp. 117-124
Author(s):  
Dodik Suprapto ◽  
Lilik Eka Radiati ◽  
Chanif Mahdi ◽  
Herly Evanuarini
Keyword(s):  
Microbial Activity ◽  
Electrical Resistance ◽  
Production Capacity ◽  
Ambient Air ◽  
Ozone Exposure ◽  
Ozone Treatment ◽  
Plate Count ◽  
Fresh Milk ◽  
Total Plate Count ◽  
Dairy Milk

The aim of this study was to evaluate the effect of ozone exposure to the physicochemical and microbial activity in dairy milk. The research material was fresh milk from dairy cows and ozone was produced by commercial ozone generator brand HANACO, production capacity up to 0.702 mg/min at 24-27ºC with oxygen source coming from ambient air in the nature. The experiment used ozone treatments for 0, 10, 20, and 30 min with variable of analysis such as density, protein, fat, electrical resistance, total plate count, and malondialdehyde which was analyzed using One Way Annova. The results showed that ozone treatment had no significant effect on the density, protein and fat in dairy milk, but had significant (P<0.05) effect on the electrical resistance, total plate count, and production of malondialdehyde. Electrical resistance and malondialdehyde were increased, while total plate count was decreased over time with the ozone exposure. Ozonation is possible to reducing yield loss on milk production that is caused by microbial activity without changing the physicochemical properties of dairy milk.

scholarly journals The protective performance of reusable cloth face masks, disposable procedure masks, KN95 masks and N95 respirators: Filtration and total inward leakage

PLoS ONE ◽  
2021 ◽  
Vol 16 (10) ◽  
pp. e0258191
Author(s):  
Scott Duncan ◽  
Paul Bodurtha ◽  
Syed Naqvi
Keyword(s):  
Geometric Mean ◽  
Particle Diameter ◽  
Standing Position ◽  
Filtration Efficiency ◽  
Protection Factor ◽  
Respiratory Illnesses ◽  
Particle Penetration ◽  
Preventive Health Measure ◽  
Materials Used ◽  
N95 Respirators

Face coverings are a key component of preventive health measure strategies to mitigate the spread of respiratory illnesses. In this study five groups of masks were investigated that are of particular relevance to the SARS-CoV-2 pandemic: re-usable, fabric two-layer and multi-layer masks, disposable procedure/surgical masks, KN95 and N95 filtering facepiece respirators. Experimental work focussed on the particle penetration through mask materials as a function of particle diameter, and the total inward leakage protection performance of the mask system. Geometric mean fabric protection factors varied from 1.78 to 144.5 for the fabric two-layer and KN95 materials, corresponding to overall filtration efficiencies of 43.8% and 99.3% using a flow rate of 17 L/min, equivalent to a breathing expiration rate for a person in a sedentary or standing position conversing with another individual. Geometric mean total inward leakage protection factors for the 2-layer, multi-layer and procedure masks were <2.3, while 6.2 was achieved for the KN95 masks. The highest values were measured for the N95 group at 165.7. Mask performance is dominated by face seal leakage. Despite the additional filtering layers added to cloth masks, and the higher filtration efficiency of the materials used in disposable procedure and KN95 masks, the total inward leakage protection factor was only marginally improved. N95 FFRs were the only mask group investigated that provided not only high filtration efficiency but high total inward leakage protection, and remain the best option to protect individuals from exposure to aerosol in high risk settings. The Mask Quality Factor and total inward leakage performance are very useful to determine the best options for masking. However, it is highly recommended that testing is undertaken on prospective products, or guidance is sought from impartial authorities, to confirm they meet any implied standards.

scholarly journals Bacteraemia associated with a vancomycin-resistant Enterococcus gallinarum strain harbouring both the vanA and vanC1 genes

2008 ◽  
Vol 57 (2) ◽  
pp. 244-245 ◽  
Author(s):  
Vânia Lúcia Carreira Merquior ◽  
Felipe Piedade Gonçalves Neves ◽  
Rachel Leite Ribeiro ◽  
Rafael Silva Duarte ◽  
Elizabeth de Andrade Marques ◽  
...  
Keyword(s):  
Bloodstream Infection ◽  
Surgical Patient ◽  
Invasive Infection ◽  
Vancomycin Resistant Enterococcus ◽  
First Report ◽  
Vancomycin Resistant ◽  
Enterococcus Gallinarum ◽  
High Level

A case of a post-surgical patient who developed a fatal bloodstream infection caused by high-level vancomycin-resistant Enterococcus gallinarum is reported. The isolate was found to carry both the vanC1 and vanA genes. This is the first report of an invasive infection associated with a vanA E. gallinarum isolate in Brazil.

scholarly journals Frequency of leucism in a colony of Anoura geoffroyi (Chiroptera: Phyllostomidae) roosting in a ferruginous cave in Brazil

2019 ◽  
Vol 19 (3) ◽  
Author(s):  
Aline da Silva Reis ◽  
Robson de Almeida Zampaulo ◽  
Sônia Aparecida Talamoni
Keyword(s):  
Gene Expression ◽  
Skin Pigmentation ◽  
Recessive Gene ◽  
Minas Gerais ◽  
Entire Body ◽  
Partial Loss ◽  
First Report ◽  
Natural Color ◽  
High Level ◽  
Anoura Geoffroyi

Abstract: We provide the first report of the frequency of leucism for a species of Neotropical bat. Leucism is an anomaly of the skin pigmentation of an animal that manifests itself as the total or partial loss of the natural color of the species, and can affect part of or the entire body. During a study involving capture and marking individuals of a population of A. geoffroyi residing in a cave in the Brazilian state of Minas Gerais, seven individuals with some degree of depigmentation were recorded out of 616 individuals marked, for a frequency of 1.1%. Since leucism is due to recessive gene expression, these findings may indicate that the population is isolated and possesses a high level of endogamy. Factors that may be responsible for this condition in the studied population remain unknown.

scholarly journals COVID-19 Disease in Children: What Dentists Should Know and Do to Prevent Viral Spread. The Italian Point of View

2020 ◽  
Vol 17 (10) ◽  
pp. 3642
Author(s):  
Gianmaria F. Ferrazzano ◽  
Aniello Ingenito ◽  
Tiziana Cantile
Keyword(s):  
Pediatric Dentistry ◽  
Point Of View ◽  
Healthcare Personnel ◽  
Viral Spread ◽  
Dental Procedures ◽  
Management Protocol ◽  
Patient Health ◽  
Pediatric Dentists ◽  
High Level ◽  
Dental Emergency

Coronavirus disease 2019 (COVID-19) has spread rapidly across the globe, becoming a major public health challenge not for China only, but also for countries around the world. Despite worldwide efforts to contain viral spread, the outbreak has not been stopped yet. Among healthcare personnel, dentists seem to be at elevated risk of exposure to COVID-19. This risk is even more serious in pediatric dentistry, since affected children, frequently, present an asymptomatic, mild or moderate clinical viral infection and, therefore, they may play a major role in community-based COVID-19 transmission. To date, despite no universal guidelines are available for dental procedures in pediatric dentistry during COVID-19 outbreak, routine dental practice should be postponed and only severe dental emergencies must be treated. In the case of a dental emergency, involving a pediatric patient, dentists should be aware of which recommended management protocol can be adopted during the practice to protect patient health, to safeguard their-self and to prevent viral transmission. The aim of this paper is to provide clinical recommendations, presenting a needed tool for dentists to allow a valid and safe how-to-do protocol. Pediatric dentists should keep a high level of awareness to help patients, minimize risk and prevent viral spread.

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