Jui-Wen Ma 1,2, Bin-Syuan Huang 1 , Chu-Wei Hsu 1, Chun-Wei Peng 1, Ming-Long Cheng 1,Jung-Yie Kao 2, Tzong-Der Way 2,3,4, Hao-Chang Yin 1,* and Shan-Shue Wang 5,*

1 Unique Biotech Co., Ltd., Rm. 1, 22 F, No. 56, Minsheng 1st Road, Xinxing District, Kaohsiung 800, Taiwan;

https://a26154295@gmail.com/ (J.-W.M.); https://chiralrecognize@gmail.com/ (B.-S.H.); https://wei751001@gmail.com/ (C.-W.H.);

https://f08220927@gmail.com/ (C.-W.P.); https://great.tree00@msa.hinet.net/ (M.-L.C.)

2 Institute of Biochemistry, College of Life Science, National Chung Hsing University, Received: 24 February 2017; Accepted: 17 March 2017; Published: 22 March 2017

DOI: 10.3390/ijerph14030329

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Abstract: 

In this study, a chlorine dioxide solution (UC-1) composed of chlorine dioxide was produced using an electrolytic method and subsequently purified using a membrane. UC-1 was determined to contain 2000 ppm of gaseous chlorine dioxide in water. The efficacy and safety of UC-1 were evaluated. The antimicrobial activity was more than 98.2% reduction when UC-1 concentrations were 5 and 20 ppm for bacteria and fungi, respectively. The half maximal inhibitory concentrations (IC50) of H1N1, influenza virus B/TW/71718/04, and EV71 were 84.65 ± 0.64, 95.91 ± 11.61, and 46.39 ± 1.97 ppm, respectively. A 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) test revealed that the cell viability of mouse lung fibroblast L929 cells was 93.7% at a 200 ppm UC-1 concentration that is higher than that anticipated in routine use. Moreover, 50 ppm UC-1 showed no significant symptoms in a rabbit ocular irritation test. In an inhalation toxicity test, treatment with 20 ppm UC-1 for 24 hours showed no abnormality and no mortality in clinical symptoms and normal functioning of the lung and other organs. A ClO2 concentration of up to 40 ppm in drinking water did not show any toxicity in a subchronic oral toxicity test. Herein, UC-1 showed favorable disinfection activity and a higher safety profile tendency than in previous reports.

Zoltán Noszticzius, Maria Wittmann*, Kristóf Kály-Kullai, Zoltán Beregvári, István Kiss, László Rosivall, János Szegedi

1 Department of Physics, Budapest University of Technology and Economics, Budapest, Hungary 2 Jósa András Hospital, Nyíregyháza, Hungary 3 St. Imre Hospital, Budapest, Hungary 4 Semmelweis University, Budapest, Hungary

https://doi.org/10.1371/journal.pone.0079157

Abstract

Background/Aims: ClO₂, the so-called “ideal biocide”, could also be applied as an antiseptic if it was understood why the solution killing microbes rapidly does not cause any harm to humans or animals. Our aim was to find the source of that selectivity by studying its reaction-diffusion mechanism both theoretically and experimentally.

Methods: ClO₂ permeation measurements through protein membranes were performed and the time delay of ClO₂ transport due to reaction and diffusion was determined. To calculate ClO₂ penetration depths and estimate bacterial killing times, approximate solutions of the reaction-diffusion equation were derived. In these calculations, evaporation rates of ClO₂ were also measured and taken into account.

Results: The rate law of the reaction-diffusion model predicts that the killing time is proportional to the square of the characteristic size (e.g. diameter) of a body, thus small ones will be killed extremely fast. For example, the killing time for a bacterium is on the order of milliseconds in a 300 ppm ClO₂ solution. Thus, a few minutes of contact time (limited by the volatility of ClO₂) is quite enough to kill all bacteria, but short enough to keep ClO₂ penetration into the living tissues of a greater organism safely below 0.1 mm, minimizing cytotoxic effects when applying it as an antiseptic. Additional properties of ClO₂ , advantageous for an antiseptic, are also discussed. Most importantly, bacteria are not able to develop resistance against ClO₂ as it reacts with biological thiols which play a vital role in all living organisms.

Conclusion: Selectivity of ClO₂ between humans and bacteria is based not on their different biochemistry, but on their different size. We hope to initiate clinical applications of this promising local antiseptic.

Jinsung Yang1,4, Simon J. L. Petitjean1,4, Melanie Koehler1, Qingrong Zhang1, Andra C. Dumitru1, Wenzhang Chen2, Sylvie Derclaye1, Stéphane P. Vincent2, Patrice Soumillion1 & David Alsteens1,3✉

DOI: 10.1038/s41467-020-18319-6

Study of the interactions established between the viral glycoproteins and their host receptors is of critical importance for a better understanding of virus entry into cells. The novel coronavirus SARS-CoV-2’s entry into host cells is mediated by its spike glycoprotein (S-glycoprotein), and the angiotensin-converting enzyme 2 (ACE2) has been identified as a cellular receptor. Here, we use atomic force microscopy to investigate the mechanisms by which the S-glycoprotein binds to the ACE2 receptor. We demonstrate, both on model surfaces and on living cells, that the receptor binding domain (RBD) serves as the binding interface within the S-glycoprotein with the ACE2 receptor and extract the kinetic and thermodynamic properties of this binding pocket. Altogether, these results provide a picture of the established interaction on living cells. Finally, we test several binding inhibitor peptides targeting the virus’s early attachment stages, offering new perspectives in the treatment of the SARS-CoV-2 infection.

Zhenbang Zhu, Yang Guo, Piao Yu, Xiaoying Wang, Xiaoxiao Zhang, Wenjuan Dong,

Xiaohong Liu, Chunhe Guo⁎

State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, North Third Road, Guangzhou Higher Education Mega Center, Guangzhou, Guangdong

510006, PR China

https://doi.org/10.1016/j.meegid.2018.11.002

ABSTRACT

Porcine reproductive and respiratory syndrome virus (PRRSV) causes a great economic loss to the swine industry globally. Current prevention and treatment measures are not effective in controlling the outbreak and spread of porcine reproductive and respiratory syndrome (PRRS). In other words, new antiviral strategies are urgently needed. Chlorine dioxide (ClO₂ ) is regarded as a broad-spectrum disinfectant with strong inhibitory effects on microbes and parasites. The purpose of this study was to evaluate the inhibitory effects and underlying molecular mechanisms of ClO₂ against PRRSV infection in vitro. Here, we identified that ClO₂ (the purity is 99%) could inhibit the infection and replication of PRRSV in both Marc-145 cells and porcine alveolar macrophages (PAMs). ClO₂ could block PRRSV binding to cells rather than internalization and release, suggesting that ClO₂ blocks the first stage of the virus life cycle. We also demonstrated that the inhibition exerted by ClO₂ was attributed to the degradation of PRRSV genome and proteins. Moreover, we confirmed that ClO₂ could decrease the expression of inflammatory cytokines induced by PRRSV. In summary, ClO₂ is an efficient agent and potently suppresses PRRSV infection in vitro.

Volume 9 Issue 3 – 2021

George Georgiou

Da Vinci BioSciences Research Centre, Cyprus

Correspondence: George Georgiou, Director, Da Vinci

BioSciences Research Centre Larnaca, Cyprus,

Email

Received: June 29, 2021 | Published: July 30, 2021

 DOI: 10.15406/jbmoa.2021.09.00306

Abstract

Antimicrobial-resistant (AMR) infections currently claim at least 50,000 lives each year across Europe and the US alone, with many hundreds of thousands more dying in other areas of the world. In 15 European countries, more than 10% of bloodstream Staphylococcus aureus infections are caused by methicillin-resistant strains (MRSA), with several of these countries seeing resistance rates closer to 50%. Moreover, while the number of antibiotic-resistant infections is on the rise, the number of new antibiotics is declining. It is therefore imperative that new, novel treatments of AMR are sought, and this is the premise of this research – using natural substances to eradicate MRSA that do not create further resistance. Chlorine dioxide used in vitro has been our main focus of this research, as it was the most effective compared to other natural substances tested.

Orsolya Láng1 & Krisztina S. Nagy2,3 & Julia Láng1 & Katalin Perczel-Kovách2,4 & Anna Herczegh5 & Zsolt Lohinai5 &

Gábor Varga2 & László Kőhidai1

Received: 16 June 2020 /Accepted: 1 October 2020

https://doi.org/10.1007/s00784-020-03618-5

Abstract

Objectives Periodontal ligament stem cells (PDLSCs) have an important significance as their high proliferative capacity and multipotent differentiation provide important therapeutic potential. The integrity of these cells is frequently disturbed by the routinely used irrigative compounds applied as periodontal or endodontic disinfectants (e.g., hydrogen peroxide (H₂O₂) and chlorhexidine (CHX)). Our objectives were (i) to monitor the cytotoxic effect of a novel dental irrigative compound, chlorine dioxide (ClO₂ ), compared to two traditional agents (H₂O₂, CHX) on PDLSCs and (ii) to test whether the aging factor of PDLSC cultures determines cellular responsiveness to the chemicals tested.

Methods Impedimetry (concentration-response study), WST-1 assays (WST = water soluble tetrazolium salt), and morphology analysis were performed to measure changes in cell viability induced by the 3 disinfectants; immunocytochemistry of stem cell markers (STRO-1, CD90, and CD105) measured the induced mesenchymal characteristics.

Results Cell viability experiments demonstrated that the application of ClO₂ does not lead to a significant decrease in viability of PDLSCs in concentrations used to kill microbes. On the contrary, traditional irrigants, H2O2, and CHX are highly toxic on PDLSCs. Aging of PDLSC cultures (passages 3 vs. 7) has characteristic effects on their responsiveness to these agents as the increased expression of mesenchymal stem cell markers turns to decreased.

Conclusions and clinical relevance While the active ingredients of mouthwash (H2O2, CHX) applied in endodontic or periodontitis management have a serious toxic effect on PDLSCs, the novel hyperpure ClO₂ is less toxic, providing an environment favoring dental structure regenerations during disinfectant interventions.

Robert O Young 

Universal Medical Imaging Group, USA

Correspondence: Robert O Young, pH Miracle Inc., 16390 Dia del Sol, Valley Center, California, 92082, USA, Tel 760 751 8321

Received: December 26, 2015 | Published: October 8, 2016

Citation: Young RO (2016) Chlorine Dioxide (ClO₂ ) As a Non-Toxic Antimicrobial Agent for Virus, Bacteria and Yeast (Candida Albicans). Int J Vaccines Vaccin 2(6): 

DOI:10.15406/ijvv.2016.02.00052

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Abstract

The use of a family of chemical agents, releasing active species of oxygen, effective against infectious microorganisms and viruses is described with emphasis on Chlorine Dioxide (ClO₂ ), one of the oxides of chlorine. Also discussed are ozone, hypochlorite, periodate and the known mechanisms of action by which certain white blood cells attach and eradicate infectious microorganisms and primitive bacteria also known as viruses.

Explanation of the biochemical mechanisms of acid of ClO₂ as an anti-microbial agent, is presented. Particular attention is given to Candida albicans, cytomegalovirus, polio virus, Herpes I and II, HTLV-III and Pseudomonas responding to the clinical application of ClO₂ . It is implied that these biochemical mechanisms are so fundamental that the development of resistant strains of bacteria and/or yeast would not occur with other anti-infectious agents. Limited lists of health abnormalities that respond to ClO₂  are discussed.

Jing Cao1,§ Yirong Shi1,§ Min Wen1,§ Yuanyuan Peng1 Qiqi Miao1 Xiaoning Liu1

Mingbin Zheng2 Tetsuya Asakawa2,* Hongzhou Lu2,3,*

1 Department of Nursing, National Clinical Research Center for Infectious Diseases, Third People’s Hospital of Shenzhen, Shenzhen, Guangdong, China 2 Institute of Neurology, National Clinical Research Center for Infectious Diseases, Third People’s Hospital of Shenzhen, Shenzhen, Guangdong, China 3 Department of Infectious Diseases, National Clinical Research Center for Infectious Diseases, Third People’s Hospital of Shenzhen, Shenzhen, Guangdong, China

DOI: 10.5582/bst.2022.01495

 Summary Keywords: chlorine dioxide (ClO₂ ), nasal irrigation, COVID-19, SARS-CoV-2, respiratory infectious diseases.

Chlorine dioxide (ClO₂ ) is a high-level disinfectant that is safe and widely used for sterilization. However, due to limitations in preparing a stable solution, direct use of ClO₂ in the human body is limited. Nasal irrigation is an alternative therapy used to treat respiratory infectious diseases. This study provides a brief summary of the available evidence regarding the safety and efficacy of using ClO₂  directly on the human body, as well as the use of nasal irrigation to treat COVID-19. Based on the available information and a preliminary experiment that evaluated the efficacy and safety of ClO₂ , a concentration of 25-50 ppm was considered appropriate for nasal irrigation to treat COVID-19. This finding requires further verification. Nasal irrigation with ClO₂ can be considered as a potential alternative therapy to treat respiratory infectious diseases, particularly COVID-19.

George Georgiou, 

2022. Eradication of Borrelia 

Burgdoferi in vitro using Chlorine 

Dioxide: A Novel Approach, 

Medical Research Archives, 

[online] 10(11). 

DOI: https://doi.org/10.18103/mra.v10i11.3279

ABSTRACT Lyme disease, which is caused by the spirochete Borrelia burgdorferi, is the most prevalent tick-borne illness in the world today and has grown into a major public health problem during the last decade, despite decades of efforts from various health professionals. The conventional treatment for Lyme disease is the use of a variety of antibiotics, but relapse often occurs when antibiotics are discontinued. There are several reasons why this relapse may occur, given that B. burgdorferi is a pleomorphic microorganism that can convert from vegetative spirochetes to a variety of different round bodies and biofilm colonies. Therefore, there is an urgent need for novel approaches that can eliminate all these different morphologies. This has challenged many health practitioners around the world, not to mention the suffering of many afflicted people. In this study, Chlorine dioxide (CD) at different concentrations was tested for its effectiveness in vitro against B. burgdorferi using combined fluorescent and darkfield microscopy with Live-or-Dye staining methods. Our experiments demonstrated that it is possible to completely eradicate all forms of B. burgdorferi at specific concentrations of Chlorine dioxide. Our extensive research has shown that Chlorine dioxide can be used for the eradication of B. burgdorferi morphologies. At certain concentrations of chlorine dioxide above 2 ppm, the Borrelia morphologies appear to be eradicated as there is no motility of either spirochetes or round bodies, only biofilms visible. However, incubating again for another 7 days resulted in the Borrelia being motile again as they come out of the biofilms. We, therefore, decided to conduct each experiment with what we termed the Regrowth Kill Test (RKT) by incubating the initial sample with the CD in an incubator at 37 degrees Celsius in the Campypack for 7 days. It appeared that the biofilms that are quickly formed as soon as the CD is added in the initial experiment broke up and released small spirochetes and round bodies of different morphologies. After numerous RKT experiments, it was determined that the concentration that resulted in a near-complete disinfection of the spirochetes as well as round bodies was 30 ppm CD.

Enrique A. Martínez

Universidad Católica del Norte, Coquimbo, Chile

https://doi.org/10.15342/ijms.7.229

ABSTRACT

This article is written to encourage medical teams from all over the world to contact the COVID-19 patients already treated with Chlorine Dioxide in Solution (CDS), a water-soluble gas. To also contact their medical teams accompanying the study cases in order to verify the actual health conditions of patients. Finally, the invitation is to question whether CDS should be tried in their respective local healthcare environments, as it is of low cost, it seems highly effective against all viral infections, and it has almost no secondary effects.

Jaiprakash G. Shewale1 | H. Carl Gelhaus2 | James L. Ratcliff1 | Yvonne L. Hernandez-Kapila3 1 Rowpar Pharmaceuticals, Inc., Scottsdale, Arizona, USA 2 MRIGlobal, Kansas City, Missouri, USA 3 Division of Periodontology, Department of Orofacial Sciences, University of California, San Francisco, San Francisco, California, USA

 DOI: 10.1111/odi.14044

Abstract 

Objective: To determine the in vitro antiviral activity of oral care products containing stabilized chlorine dioxide toward infectious viruses that harbor in the oral cavity. Specifically, severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), SARSCoV, human coronavirus (HCoV) 229E, influenza A (H3N2), rhinovirus type 14, adenovirus type 5, and herpes simplex virus (HSV) type 1 and 2 were examined. Methods: Validated in vitro suspension virucidal assays were used. The test product was mixed with the test virus for 30, 60, or 120 s, neutralized with sodium thiosulfate, serially diluted in dilution medium in a 96-well plate, and incubated in a carbon dioxide incubator for 7 days. The 50% Tissue Culture Infectious Dose per milliliter was determined. Results: Two rinses, one oral spray, and one fluoride toothpaste showed log reduction of severe acute respiratory syndrome coronavirus-2 ranging from 1.81 to 2.98 and of influenza A from 2.58 to 4.13, respectively, within 30 s of contact time; similar results were obtained at 60 s. Further, the Ultra Sensitive rinse showed 0.19, 0.75, 1.58, 1.75, 2.66, and 3.24 log reduction of severe acute respiratory syndrome coronavirus, human coronavirus 229E, rhinovirus type 14, adenovirus type 5, and herpes simplex virus type 1 and type 2, respectively, within 30 s of contact time. Conclusion: Stabilized chlorine dioxide containing ClōSYS® oral care products reduced the viral load of multiple viruses within 30 s. The results warrant further investigation for potential in vivo applications.

Sabina Andreu 1,2,* , Inés Ripa 1,2, Raquel Bello-Morales 1,2 and José Antonio López-Guerrero 1,2

1 Departamento de Biología Molecular, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain; ines.ripa@cbm.csic.es (I.R.); raquel.bello-morales@uam.es (R.B.-M.); ja.lopez@uam.es (J.A.L.-G.) 2 Centro de Biología Molecular Severo Ochoa, Spanish National Research Council—Universidad Autónoma de Madrid (CSIC-UAM), Cantoblanco, 28049 Madrid, Spain

• Correspondence: sandreu@cbm.csic.es

https://doi.org/10.3390/v13030531

Abstract: 

The emergent human coronavirus SARS-CoV-2 and its high infectivity rate has highlighted the strong need for new disinfection systems. Evidence has proven that airborne transmission is an important route of spreading for this virus. Therefore, this short communication introduces CLODOS Technology®, a novel strategy to disinfect contaminated surfaces. It is a product based on stable and 99% pure chlorine dioxide, already certified as a bactericide, fungicide, and virucide against different pathogens. In this study, CLODOS Technology®, by direct contact or thermonebulization, showed virucidal activity against the human coronavirus HCoV-229E at non-cytotoxic doses. Different conditions such as nebulization, exposure time, and product concentration have been tested to standardize and optimize this new feasible method for disinfection.

Mitchell Brent Liester Department of Psychiatry, University of Colorado School of Medicine, P.O. Box 302 Monument, CO 80132, USA. Received 25 May 2021; Accepted 23 August 2021. 

DOI: 10.5897/IJMMS2021.1461

Abstract

Chlorine dioxide has been condemned as a dangerous poison and has been touted as a cure for COVID-19. This narrative review examines the controversy surrounding the use of aqueous chlorine dioxide by investigating evidence-based research articles, government documents, press reports, and the results of the first clinical trial utilizing chlorine dioxide as a treatment for COVID-19. Chlorine dioxide was found to be employed by numerous industries for antimicrobial and other uses. Aqueous chlorine dioxide was found to be safe when ingested in low doses, but when ingested in high doses, it can cause adverse hematologic and renal effects. Additionally, chlorine dioxide was found to be a strong and rapidly acting virucide with activity against a wide range of viruses. Results of the first clinical trial utilizing chlorine dioxide to treat COVID-19 are reviewed, and this molecule is found to be a safe and effective treatment. A dispassionate review of the evidence-based research literature finds preliminary evidence supporting the opinion that aqueous chlorine dioxide may be a safe and effective treatment of COVID-19, and likely for other viral illnesses as well. Further studies are needed to confirm these findings and to explore potential uses of chlorine dioxide.

George Georgiou – Principal Investigator – https://admin@docgeorge.com/

Agnieszka Kotzé – Researcher – https://aggie.kotze@gmail.com/

https://doi.org/10.18103/mra.v11i7.2.4218

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ABSTRACT

Bacterial Antibiotic Resistance (AMR) is a problem in all regions, with six pathogens accounting for 73.4% of deaths attributable to bacterial AMR, namely Escherichia coli (E. coli), Staphylococcus aureus (S. aureus), Klebsiella pneumoniae (K. pneumoniae), Streptococcus pneumoniae (S. pneumoniae), Acinetobacter baumannii (A. baumannii), and Pseudomonas aeruginosa (P. aeruginosa). The World Health Organization instigated a Global Action Plan on AMR in 2021, which is still active – healthcare costs for AMR run into many billions of dollars worldwide. A Review on Antimicrobial Resistance commissioned by the British Government argued that AMR could kill 10 million people per year by 2050 and has emerged as one of the greatest public health threats of the 21st century. Just one AMR pathogen, Methicillin-Resistant Staphylococcus aureus (MRSA), caused more than 100,000 deaths worldwide, with the other four pathogens covered in this research causing as many deaths again. This research has focused on studying chlorine dioxide’s effectiveness in eradicating five different AMR bacteria in vitro as a novel and effective treatment. This study used different chlorine dioxide concentrations with five antibiotic-resistant bacteria, ranging from 1 – 7 ppm concentrations. Disinfection studies were compared to controls, and the results demonstrated a greater than 95% disinfection with concentrations of 7 ppm. Chlorine dioxide is a size-selective antimicrobial agent that can kill micron-sized organisms rapidly but will not cause actual harm to much larger organisms like animals or humans as it cannot penetrate deeply into their living tissues. It is safe when used in low concentrations for short durations. Clinical trials must be undertaken to gain experience in the best dosages and protocols to eradicate antibiotic-resistant microorganisms from the body.

R. ZONI, R. ZANELLI, E. RIBOLDI, L. BIGLIARDI, G. SANSEBASTIANO

Department of Public Health, Sec. Hygiene, University of Parma, Italy

https://pubmed.ncbi.nlm.nih.gov/18274345/

Introduction. The aim of this study was to evaluate the efficacy of ClO₂ with regard to viruses which show a particular resistance to oxidizing agents such as HAV, Norwalk, and Norwalk-like viruses, and which play an important role in the epidemiology of viral foodborne diseases.

In the food industry, disinfection of processing systems and equipment is a very important instrument to prevent secondary contamination and to guarantee food safety. Among disinfectants, chlorine dioxide (ClO₂ ) presents good efficacy at a wide range of pH values. Its action is rapid and generates few reaction byproducts compared to hypochlorite. Experimental studies have highlighted that ClO₂ shows good bactericidal activity and is also active towards viruses. Furthermore, the low concentrations and low contact times required to obtain microbial load reduction are favorable elements for the application of this compound in industrial sanitizing practices.

Methods. As it is impossible to cultivate the Norwalk virus in vitro, we tested the resistance of Feline calicivirus (F9 strain) vs. ClO₂ , in comparison with HAV (strain HM-175) and Coxsackie B5. Chlorine dioxide was used at concentrations ranging from 0.2 to 0.8 mg/l in a water solution, at pH 7 and at +20 °C. Viral suspensions were added to the disinfecting solution and, at pre-set times, were sampled to undergo titration after blocking the disinfectant action with thiosulfate 0.05 M. Based on the data obtained, mean reduction times were calculated for 99%, 99.9%, and 99.99% using the regression analysis model.

Results. As regards Feline calicivirus, at a concentration of 0.8 mg/l of ClO₂ , we obtained the complete elimination of the viral titre in 2 min, while 30 min were required at concentrations of 0.2 mg/l. Coxsackie B5 showed a similar behavior, being completely inactivated in 4 min with 0.4 mg/l of ClO2, and after 30 min at a concentration of 0.2 mg/l. Inactivation was quicker for HAV, which was eliminated after only 30 sec at a concentration of 0.8 mg/l and after 5 min at 0.4 mg/l.

Conclusion. Our data show that for complete inactivation of HAV and Feline calicivirus, concentrations ≥ 0.6 mg/l are required. This observation is true for Coxsackie B5 as well, but this virus has shown good sensitivity at all concentrations tested according to regression analysis results. For Feline calicivirus and HAV, at low concentrations of disinfectant, prolonged contact times were needed to obtain a 99.99% reduction of viral titres (about 16 and 20 minutes respectively).

Michele Totaro, Federica Badalucco, Anna Laura Costa, Benedetta Tuvo, Beatrice Casini, Gaetano Privitera, Giovanni Battista Menchini Fabris, and Angelo Baggiani

1. Department of Translational Research and the New Technologies in Medicine and Surgery, University of Pisa, 56126 Pisa, Italy

2. San Rossore Dental Unit, 56122 San Rossore, Italy

https://doi.org/10.3390/pathogens10081017

Abstract

A viral spread occurrence such as the SARS-CoV-2 pandemic has prompted the evaluation of different disinfectants suitable for a wide range of environmental matrices. Chlorine dioxide (ClO₂ ) represents one of the most-used virucidal agents in different settings effective against both enveloped and nonenveloped viruses. This narrative synthesis is focused on the effectiveness of ClO₂ applied in healthcare and community settings in order to eliminate respiratory transmitted, enteric, and bloodborne viruses. Influenza viruses were reduced by 99.9% by 0.5–1.0 mg/L of ClO₂ in less than 5 min. Higher concentration (20 mg/L) eliminated SARS-CoV-2 from sewage. ClO₂ concentrations from 0.2 to 1.0 mg/L ensured at least a 99% viral reduction of AD40, HAV, Coxsackie B5 virus, and other enteric viruses in less than 30 min. Considering bloodborne viruses, 30 mg/L of ClO₂ can eliminate them in 5 min. Bloodborne viruses (HIV-1, HCV, and HBV) may be completely eliminated from medical devices and human fluids after a treatment with 30 mg/L of ClO₂ for 30 min. In conclusion, ClO₂ is a versatile virucidal agent suitable for different environmental matrices.

Authors: K. Kály-Kullai, M. Wittmann, Z. Noszticzius, and László Rosivall

DOI: https://doi.org/10.1556/2060.2020.00015

 Introduction

Motivation Viruses have caused many epidemics throughout human history. The novel coronavirus [10] is just the latest example. A new viral outbreak can be unpredictable, and development of specific defense tools and countermeasures against the new virus remains time-consuming even in today’s era of modern medical science and technology. In the lack of effective and specific medication or vaccination, it would be desirable to have a nonspecific protocol or substance to render the virus inactive, a substance/protocol, which could be applied whenever a new viral outbreak occurs. This is especially important in cases when the emerging new virus is as infectious as SARS-CoV-2 [4].

Aim and structure of the present communication In this editorial, we propose to consider the possibility of developing and implementing antiviral protocols by applying high purity aqueous chlorine dioxide (ClO₂ ) solutions. The aim of this proposal is to initiate research that could lead to the introduction of practical and effective antiviral protocols. To this end, we first discuss some important properties of the ClO₂ molecule, which make it an advantageous antiviral agent, then some earlier results of ClO₂ gas application against viruses will be reviewed. Finally, we hypothesize on methods to control the spread of viral infections using aqueous ClO₂ solutions.

Previous experience and background of using ClO₂ as an antiviral agent Inactivating viruses with ClO₂ in aqueous phase To our present knowledge, an aqueous solution of ClO₂ is able to inactivate all types of viruses. Disinfectants (in water phase) are compared by their CT values, which is the concentration (measured in mg/L) multiplied by the contact time (measured in minute). In CT tables, ClO₂ is indicated for viruses in general, without mentioning any exemptions. For example, according to [6], a CT value of 8.4 mg × min/L is needed to achieve a four-orders-of-magnitude (“4 log” or “99.99%”) inactivation of viruses in an aqueous medium at 25 °C.

Chemical mechanism of virus inactivation: reaction of ClO₂ with amino acid residues In 1986, Noss et al. [19] proved that the inactivation of bacterial virus f2 by ClO₂ was due to its reactions with the viral capsid proteins, and almost no inactivation of the infectious viral RNA occurred [8] when that was treated with ClO₂ separately. They found [19], however, that three discrete chemical moieties in the viral protein, namely the cysteine, tyrosine, and tryptophan amino acid residues were able to react with ClO₂ rapidly. In 1987, Tan et al. [28] tested the reactivity of ClO₂ on 21 free amino acids. ClO₂ reacted only with six amino acids dissolved in 0.1 M sodium phosphate buffer, pH 6.0. The reaction with cysteine, tryptophan, and tyrosine was too rapid to be followed by their technique. Three further amino acids (histidine, hydroxyproline, and proline) reacted with ClO₂ much more slowly, at a measurable rate.

The reactivity of the three fast-reacting amino acids (cysteine [12], tyrosine [17], and tryptophan [27]) was studied in Margerum’s laboratory between 2005 and 2008. They found that cysteine had the highest reactivity among these amino acids. From their experimental data they calculated second order-rate constants (at pH 7.0, 25 °C and 1 M ionic strength) and obtained the following sequence: cysteine 6.9 × 106 M−1 s−1 >> tyrosine 1.3 × 105 M−1 s−1 > tryptophan 3.4 × 104 M−1 s−1 >> guanosine 5’-monophosphate 4.5 × 102 M−1 s−1. (They studied guanosine 5’-monophosphate [18] as a model compound for guanine in nucleic acids. Data presented here are taken from Table 3 of ref. [18]).

In 2007, Ogata [22] found that the antimicrobial activity of ClO₂ is based on denaturation of certain proteins, which is primarily due to the oxidative modification of the tryptophan and tyrosine residues of the two model proteins (bovine serum albumin and glucose-6-phosphate dehydrogenase) used in his experiments. In 2012, it was again Ogata who showed [23] that the inactivation of influenza virus by ClO₂ was caused by oxidation of a tryptophan residue (W153) in hemagglutinin (a spike protein of the virus), thereby abolishing its receptor-binding ability.

In this context it is interesting to remark that the spike protein of the new coronavirus SARS_CoV-2 contains 54 tyrosine, 12 tryptophan, and 40 cysteine residues [29]. If we assume that in an aqueous solution all of these residues are able to react with ClO₂ just like the free amino acids, then the inactivation of the viruses can be extremely rapid even in a very dilute (e.g., in a 0.1 mg/L) ClO₂ solution.

R. Wesley Farr and Cheryl Walton

Published online by Cambridge University Press:  21 June 2016

Infection Control & Hospital Epidemiology , Volume 14 , Issue 9 , September 1993 , pp. 527 – 529

DOI: https://doi.org/10.1086/646798

Abstract 

Objective: To study the ability of a medical waste disposal process using chlorine dioxide to inactivate human immunodeficiency virus type 1 (HIV-1).

Design: Stock HIV-1 (HTLV-IIIB strain) was treated with chlorine dioxide under the following settings: cell culture medium alone, culture medium with 25% blood, culture medium with medical supplies treated by the Condor machine (Winfield Environmental Corp., Escondido, CA). MT-2 cells in 96-well tissue culture plates were inoculated with serial tenfold dilutions of treated and untreated HIV-1. Cytopathic effect was read on day five, and the TCID50 (50% tissue culture infectious dose) was calculated.

Results: Treatment of HIV-1 with chlorine dioxide in culture medium alone resulted in a 5.25 log10 reduction in TCID50. Treatment of HIV-1 with chlorine dioxide in the presence of 25% blood caused a 6.25 log10 reduction in HIV-1 infectivity. Treatment of HIV-1 with chlorine dioxide in the presence of medical supplies treated in the Condor machine resulted in a 4.75 log10 reduction in HIV infectivity.

Conclusions: Chlorine dioxide inactivated HIV-1 in vitro. Chlorine dioxide inactivated HIV-1 in the presence of blood and in the presence of medical supplies under conditions that simulated the conditions existing in the Condor machine.

Takao Watamoto, DDS, PhD/Hiroshi Egusa, DDS, PhD/Takashi Sawase, DDS, PhD/Hirofumi Yatani, DDS, PhD PMID: 24179967

DOI: 10.11607/ijp.3465

This study aimed to clinically evaluate the disinfection efficacy of chlorine dioxide (ClO₂ ) for used dental instruments. An imprint culture technique demonstrated that ultrasonic cleaning of intraorally applied dental mirrors in 0.02% ClO₂ for 10 minutes resulted in compete removal of microorganisms for 10 subjects. Hepatitis C virus (HCV) RNA was detected by real-time polymerase chain reaction on periodontal curettes after subgingival scaling in four HCV-infected patients and was completely removed by the same treatment procedure. Therefore, the combination of ultrasonic cleaning with ClO₂ may provide an alternative to toxic disinfectants, such as glutaraldehyde and sodium hypochlorite, for disinfecting dental instruments. Int J Prosthodont 2013;26:541–544. doi: 10.11607/ijp.3465

Ming-Chun Lu . Po-Lin Chen . Da-Ji Huang . Chih-Kuo Liang . Ching-Shan Hsu . Wei-Ting Liu Received: 17 August 2019 / Accepted: 22 October 2020 Springer Nature B.V. 2020

https://doi.org/10.1007/s10453-020-09670-8(0123456789().,-volV)( 01234567

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Abstract: 

The disinfection efficiencies of two chemical disinfectants, chlorine dioxide and weak acid hypochlorous water (WAHW), were examined in the soiled room and dishwashing room of a hospital infectious disease ward in Taiwan. The investigations were conducted in two seasons, namely winter and summer, in order to examine the correlation between the bioaerosol concentration and the environmental factors. In addition, a single-daily disinfection mode (SM) and a twice-daily disinfection mode (TM) were applied in this study. The results showed that the bacteria and fungi colony counts were strongly correlated with the temperature. Both disinfectants reduced the bacteria and fungi concentrations in the considered rooms. However, of the two disinfectants, the ClO₂ showed a stronger disinfection effect than the WAHW. It means that when using ClO₂ as the disinfectant, the disinfection efficiency of the TM treatment mode is significantly better than that of the SM treatment mode. But, when using WAHW as the disinfectant, no significant difference is found between the disinfection efficiencies of the two methods. Overall, the results showed that the application of ClO₂ twice daily provided the most effective means of satisfying the Taiwan EPA guidelines for the indoor air quality of hospital medical wards.

Norio Ogata

Journal of General Virology (2012), 93, 2558–2563

Research Institute, Taiko Pharmaceutical Co., Ltd, Suita, Osaka 564-0032, Japan

https://doi.org/10.1099/vir.0.044263-0

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Airborne influenza virus infection of mice can be prevented by gaseous chlorine dioxide (ClO₂ ). This study demonstrated that ClO₂ abolished the function of the hemagglutinin (HA) of influenza A virus (H1N1) in a concentration-, time-, and temperature-dependent manner. The IC50 during a 2-min reaction with ClO₂ at 25°C was 13.7 mM, and the half-life time of HA with 100 mM ClO₂ at 25°C was 19.5 s. Peptides generated from a tryptic digest of ClO₂ -treated virus were analyzed by mass spectrometry. An HA fragment, 150NLLWLTGK157, was identified in which the tryptophan residue (W153) was 32 mass units greater than expected. The W153 residue of this peptide, which is derived from the central region of the receptor-binding site of HA, is highly conserved. It was shown that W153 was oxidized to N-formylkynurenine in ClO₂ -treated virus. It was concluded that the inactivation of influenza virus by ClO₂ is caused by oxidation of W153 in HA, thereby abolishing its receptor-binding ability.

Authors: Jia Wei Yeap, Simran Kaur, Fangfei Lou, Erin DiCaprio, Mark Morgan, Richard Linton, Jianrong Li

ASM Journals Applied and Environmental Microbiology Vol. 82, No. 1

 DOI: https://doi.org/10.1128/AEM.02489-15

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ABSTRACT

Acute gastroenteritis caused by human norovirus is a significant public health issue. Fresh produce and seafood are examples of high-risk foods associated with norovirus outbreaks. Food contact surfaces also have the potential to harbor noroviruses if exposed to fecal contamination, aerosolized vomitus, or infected food handlers. Currently, there is no effective measure to decontaminate norovirus on food contact surfaces. Chlorine dioxide (ClO₂ ) gas is a strong oxidizer and is used as a decontaminating agent in food processing plants. The objective of this study was to determine the kinetics and mechanism of ClO₂ gas inactivation of a norovirus surrogate, murine norovirus 1 (MNV-1), on stainless steel (SS) coupons. MNV-1 was inoculated on SS coupons at the concentration of 107 PFU/coupon. The samples were treated with ClO₂ gas at 1, 1.5, 2, 2.5, and 4 mg/liter for up to 5 min at 25°C and a relative humidity of 85%, and virus survival was determined by plaque assay. Treatment of the SS coupons with ClO₂ gas at 2 mg/liter for 5 min and 2.5 mg/liter for 2 min resulted in at least a 3-log reduction in MNV-1, while no infectious virus was recovered at a concentration of 4 mg/liter even within 1 min of treatment. Furthermore, it was found that the mechanism of ClO₂ gas inactivation included degradation of viral protein, disruption of viral structure, and degradation of viral genomic RNA. In conclusion, treatment with ClO₂ gas can serve as an effective method to inactivate a human norovirus surrogate on SS contact surfaces.

TAKESHI SANEKATA, TOSHIAKI FUKUDA, TAKANORI MIURA, HIROFUMI MORINO, CHEOLSUNG LEE, KEN MAEDA, KAZUKO ARAKI, TORU OTAKE, TAKUYA KAWAHATA, TAKASHI SHIBATA

https://doi.org/10.4265/bio.15.45

Abstract We evaluated the antiviral activity of a chlorine dioxide gas solution (CD) and sodium hypochlorite (SH) against feline calicivirus, human influenza virus, measles virus, canine distemper virus, human herpesvirus, human adenovirus, canine adenovirus, and canine parvovirus. CD at concentrations ranging from 1 to 100 ppm produced potent antiviral activity, inactivating ≥ 99.9% of the viruses with a 15-second treatment for sensitization. The antiviral activity of CD was approximately 10 times higher than that of SH.