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1.
Cells ; 11(11)2022 05 27.
Article in English | MEDLINE | ID: covidwho-1869481

ABSTRACT

Effective airborne transmission of coronaviruses via liquid microdroplets requires a virion structure that must withstand harsh environmental conditions. Due to the demanding biosafety requirements for the study of human respiratory viruses, it is important to develop surrogate models to facilitate their investigation. Here we explore the mechanical properties and nanostructure of transmissible gastroenteritis virus (TGEV) virions in liquid milieu and their response to different chemical agents commonly used as biocides. Our data provide two-fold results on virus stability: First, while particles with larger size and lower packing fraction kept their morphology intact after successive mechanical aggressions, smaller viruses with higher packing fraction showed conspicuous evidence of structural damage and content release. Second, monitoring the structure of single TGEV particles in the presence of detergent and alcohol in real time revealed the stages of gradual degradation of the virus structure in situ. These data suggest that detergent is three orders of magnitude more efficient than alcohol in destabilizing TGEV virus particles, paving the way for optimizing hygienic protocols for viruses with similar structure, such as SARS-CoV-2.


Subject(s)
COVID-19 , Transmissible gastroenteritis virus , Detergents/pharmacology , Humans , SARS-CoV-2 , Transmissible gastroenteritis virus/metabolism , Virion/metabolism
2.
Viruses ; 14(4)2022 03 29.
Article in English | MEDLINE | ID: covidwho-1834924

ABSTRACT

The COVID-19 pandemic caused by SARS-CoV-2 is having devastating effects on a global scale. Since common household disinfectants are often used to minimise the risk of infection in the home and work environment, we investigated the ability of some of these products to inactivate the virus. We tested generic brands of vinegar, bleach, and dishwashing detergent, as well as laboratory-grade acetic acid, sodium hypochlorite, and ethanol. Assays were conducted at room temperature (18-20 °C, 40% relative humidity), and two time points were used to reflect a quick wipe (30 s) and a brief soak (5 min). Vinegar, and its active ingredient, acetic acid, were completely ineffective at virus inactivation even when exposed to the virus at 90% v/v (a final concentration equivalent to 3.6% v/v acetic acid). In contrast, ethanol was capable of inactivating the virus at dilutions as low as 40% v/v. Dishwashing detergent effectively rendered SARS-CoV-2 inactive when diluted 100-fold (1% v/v). Bleach was found to be fully effective against SARS-CoV-2 at 0.21 g/L sodium hypochlorite after a 30 s exposure (1/200 dilution of commercial product). Given reports of infectious virus recovered from the surface of frozen packaging, we tested the persistence of infectiousness after multiple freeze-thaw cycles and found no change in infectious SARS-CoV-2 titre after seven freeze-thaw cycles. These results should help inform readers of how to effectively disinfect surfaces and objects that have potentially been contaminated with SARS-CoV-2 using common household chemicals.


Subject(s)
COVID-19 , Disinfectants , Acetic Acid/pharmacology , COVID-19/prevention & control , Detergents/pharmacology , Disinfectants/pharmacology , Ethanol/pharmacology , Humans , Pandemics , SARS-CoV-2 , Sodium Hypochlorite/pharmacology
3.
Int J Mol Sci ; 23(3)2022 Jan 18.
Article in English | MEDLINE | ID: covidwho-1625435

ABSTRACT

Spike protein of SARS-CoV-2 contains a single-span transmembrane (TM) domain and plays roles in receptor binding, viral attachment and viral entry to the host cells. The TM domain of spike protein is critical for viral infectivity. Herein, the TM domain of spike protein of SARS-CoV-2 was reconstituted in detergent micelles and subjected to structural analysis using solution NMR spectroscopy. The results demonstrate that the TM domain of the protein forms a helical structure in detergent micelles. An unstructured linker is identified between the TM helix and heptapeptide repeat 2 region. The linker is due to the proline residue at position 1213. Side chains of the three tryptophan residues preceding to and within the TM helix important for the function of S-protein might adopt multiple conformations which may be critical for their function. The side chain of W1212 was shown to be exposed to solvent and the side chains of residues W1214 and W1217 are buried in micelles. Relaxation study shows that the TM helix is rigid in solution while several residues have exchanges. The secondary structure and dynamics of the TM domain in this study provide insights into the function of the TM domain of spike protein.


Subject(s)
Detergents/pharmacology , Spike Glycoprotein, Coronavirus/chemistry , Amino Acid Sequence , COVID-19/virology , Cell Membrane/metabolism , Cross-Linking Reagents/pharmacology , Detergents/chemistry , Humans , Magnetic Resonance Spectroscopy , Micelles , Models, Molecular , Nuclear Magnetic Resonance, Biomolecular , Protein Domains/drug effects , Protein Structure, Secondary/drug effects , SARS-CoV-2/chemistry , SARS-CoV-2/metabolism , Spike Glycoprotein, Coronavirus/drug effects , Spike Glycoprotein, Coronavirus/metabolism
4.
mSphere ; 6(2)2021 04 28.
Article in English | MEDLINE | ID: covidwho-1207482

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) persists on stainless steel and plastic for up to 7 days, suggesting that coronavirus disease 2019 (COVID-19) could be spread by fomite transmission. There is limited research on the stability of SARS-CoV-2 on textiles, with the risk of textiles acting as fomites not being well understood. To date, there does not appear to be any published research on the stability of coronaviruses during laundering, which is required to determine the efficacy of current laundering policies in the decontamination of health care textiles. The aim of this study was to investigate the environmental stability of human coronaviruses HCoV-OC43 and HCoV-229E on different textile fiber types and the persistence of HCoV-OC43 on textiles during domestic and industrial laundering. This study demonstrated that human coronaviruses (5 log10 50% tissue culture infective doses [TCID50]) remain infectious on polyester for ≥72 h, cotton for ≥24 h, and polycotton for ≥6 h; HCoV-OC43 was also able to transfer from polyester to PVC or polyester after 72 h. Under clean conditions, HCoV-OC43 was not detectable on cotton swatches laundered with industrial and domestic wash cycles without temperature and detergent (≥4.57-log10-TCID50 reduction), suggesting that the dilution and agitation of wash cycles are sufficient to remove human coronaviruses from textiles. In the presence of interfering substances (artificial saliva), ≤1.78 log10 TCID50 HCoV-OC43 was detected after washing domestically without temperature and detergent, unlike industrial laundering, where the virus was completely removed. However, no infectious HCoV-OC43 was detected when washed domestically with detergent.IMPORTANCE Synthetic textiles such as polyester could potentially act as fomites of human coronaviruses, indicating the importance of infection control procedures during handling of contaminated textiles prior to laundering. This study provides novel evidence that human coronaviruses can persist on textiles for up to 3 days and are readily transferred from polyester textile to other surfaces after 72 h of incubation. This is of particular importance for the domestic laundering of contaminated textiles such as health care uniforms in the United Kingdom and United States, where there may be a risk of cross-contaminating the domestic environment. It was demonstrated that human coronaviruses are removed from contaminated textiles by typical domestic and commercial wash cycles, even at low temperatures without detergent, indicating that current health care laundering policies are likely sufficient in the decontamination of SARS-CoV-2 from textiles.


Subject(s)
COVID-19/transmission , Common Cold/transmission , Coronavirus 229E, Human/drug effects , Coronavirus OC43, Human/drug effects , Detergents/pharmacology , Textiles/virology , Cell Line , Cotton Fiber/virology , Fomites/virology , Humans , Laundering , Polyesters , SARS-CoV-2/drug effects
5.
Am J Trop Med Hyg ; 104(6): 2195-2198, 2021 04 20.
Article in English | MEDLINE | ID: covidwho-1194763

ABSTRACT

The burden on diagnostic and research laboratories to provide reliable inactivation for biological specimens to allow for safe downstream processing is high during the coronavirus disease 2019 (COVID-19) pandemic. We provide safety data regarding commonly used chemical and physical inactivation procedures that verify their effectiveness against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).


Subject(s)
Detergents/pharmacology , Disinfectants/pharmacology , SARS-CoV-2/drug effects , SARS-CoV-2/radiation effects , Virus Inactivation , Humans , Laboratories , RNA, Viral/physiology , Specimen Handling/methods
6.
Cells ; 10(3)2021 03 04.
Article in English | MEDLINE | ID: covidwho-1125522

ABSTRACT

Since the outbreak of the COVID-19 crisis, the handling of biological samples from confirmed or suspected SARS-CoV-2-positive individuals demanded the use of inactivation protocols to ensure laboratory operators' safety. While not standardized, these practices can be roughly divided into two categories, namely heat inactivation and solvent-detergent treatments. These routine procedures should also apply to samples intended for Extracellular Vesicles (EVs) analysis. Assessing the impact of virus-inactivating pre-treatments is therefore of pivotal importance, given the well-known variability introduced by different pre-analytical steps on downstream EVs isolation and analysis. Arguably, shared guidelines on inactivation protocols tailored to best address EVs-specific requirements will be needed among the analytical community, yet deep investigations in this direction have not yet been reported. We here provide insights into SARS-CoV-2 inactivation practices to be adopted prior to serum EVs analysis by comparing solvent/detergent treatment vs. heat inactivation. Our analysis entails the evaluation of EVs recovery and purity along with biochemical, biophysical and biomolecular profiling by means of a set of complementary analytical techniques: Nanoparticle Tracking Analysis, Western Blotting, Atomic Force Microscopy, miRNA content (digital droplet PCR) and tetraspanin assessment by microarrays. Our data suggest an increase in ultracentrifugation (UC) recovery following heat treatment; however, it is accompanied by a marked enrichment in EVs-associated contaminants. On the other hand, solvent/detergent treatment is promising for small EVs (<150 nm range), yet a depletion of larger vesicular entities was detected. This work represents a first step towards the identification of optimal serum inactivation protocols targeted to EVs analysis.


Subject(s)
COVID-19/blood , Containment of Biohazards/methods , Extracellular Vesicles/chemistry , Virus Inactivation , COVID-19/virology , Detergents/pharmacology , Extracellular Vesicles/drug effects , Extracellular Vesicles/genetics , Hot Temperature , Humans , MicroRNAs/analysis , Microarray Analysis , Microscopy, Atomic Force , SARS-CoV-2 , Tetraspanins/analysis , Ultracentrifugation
7.
Exp Biol Med (Maywood) ; 246(6): 740-748, 2021 03.
Article in English | MEDLINE | ID: covidwho-978883

ABSTRACT

Shortages of N95 respirators for use by medical personnel have driven consideration of novel conservation strategies, including decontamination for reuse and extended use. Decontamination methods listed as promising by the Centers for Disease Control and Prevention (CDC) (vaporous hydrogen peroxide (VHP), wet heat, ultraviolet irradiation (UVI)) and several methods considered for low resource environments (bleach, isopropyl alcohol and detergent/soap) were studied for two commonly used surgical N95 respirators (3M™ 1860 and 1870+ Aura™). Although N95 filtration performance depends on the electrostatically charged electret filtration layer, the impact of decontamination on this layer is largely unexplored. As such, respirator performance following decontamination was assessed based on the fit, filtration efficiency, and pressure drop, along with the relationship between (1) surface charge of the electret layer, and (2) elastic properties of the straps. Decontamination with VHP, wet heat, UVI, and bleach did not degrade fit and filtration performance or electret charge. Isopropyl alcohol and soap significantly degraded fit, filtration performance, and electret charge. Pressure drop across the respirators was unchanged. Modest degradation of N95 strap elasticity was observed in mechanical fatigue testing, a model for repeated donnings and doffings. CDC recommended decontamination methods including VHP, wet heat, and UV light did not degrade N95 respirator fit or filtration performance in these tests. Extended use of N95 respirators may degrade strap elasticity, but a loss of face seal integrity should be apparent during user seal checks. NIOSH recommends performing user seal checks after every donning to detect loss of appropriate fit. Decontamination methods which degrade electret charge such as alcohols or detergents should not be used on N95 respirators. The loss of N95 performance due to electret degradation would not be apparent to a respirator user or evident during a negative pressure user seal check.


Subject(s)
COVID-19/prevention & control , Decontamination/methods , N95 Respirators/supply & distribution , 2-Propanol/pharmacology , Detergents/pharmacology , Humans , Hydrogen Peroxide/pharmacology , SARS-CoV-2 , Sodium Hypochlorite/pharmacology , Static Electricity , Ultraviolet Rays
8.
Eur Rev Med Pharmacol Sci ; 24(21): 11432-11439, 2020 Nov.
Article in English | MEDLINE | ID: covidwho-934955

ABSTRACT

OBJECTIVE: Soap has been used by humankind since ancient times and was probably already known to the Sumerians. It is a fatty acid salt obtained from the reaction of a strong base with a fatty substance of animal (tallow) or plant origin (oil). This reaction is called saponification. Syndets, on the other hand, are much more recent and have been in use for about a century. In the case of liquid syndets, they are mainly alkyl sulphates and their derivatives alkyl ether sulphates while isethionates and sarcosinates are more commonly found in solid syndets. Synthetic soaps and detergents are surfactants and, as such, they have detergent properties. The way soap works accounts for its antimicrobial properties. Thanks to its amphiphilic structure, it is able to interact with the lipid membranes of microorganisms (viruses, bacteria, etc.) and inactivate them. In this coronavirus pandemic period, health authorities worldwide recommend hand washing with soap and water. We therefore wanted to provide a summary of the chemical characteristics and applications of soaps, on the one hand, and synthetic detergents, on the other. Soap is not the only product used for hand hygiene and, given the current situation, alternatives are complex and varied.


Subject(s)
Anti-Infective Agents/pharmacology , Betacoronavirus/drug effects , Coronavirus Infections/prevention & control , Detergents/pharmacology , Hand Disinfection/methods , Pandemics/prevention & control , Pneumonia, Viral/prevention & control , Soaps/pharmacology , Anti-Infective Agents/chemistry , Anti-Infective Agents/standards , COVID-19 , Communicable Disease Control/methods , Communicable Disease Control/standards , Coronavirus Infections/epidemiology , Coronavirus Infections/transmission , Coronavirus Infections/virology , Detergents/chemistry , Detergents/standards , Hand Disinfection/standards , Humans , Pneumonia, Viral/epidemiology , Pneumonia, Viral/transmission , Pneumonia, Viral/virology , SARS-CoV-2 , Soaps/chemistry , Soaps/standards
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