BPB Reports

The importance of mitigating the spread of infectious disease for public health has continued to increase over the last several decades. Many examples of emerging and re-emerging infections have appeared, including methicillin-resistant Staphylococcus aureus-derived diseases, drug-resistant tuberculosis, cholera by Vibrio cholerae, hemorrhagic colitis caused by Escherichia coli, Coronavirus Infectious Disease of 2019 (COVID-19), and so on.1,2) There is a clear need for effective disinfectants able to inactivate microorganisms without adversely affecting the human body. Chlorine dioxide and chlorine, common disinfecting and bleaching chemicals used in the food industry, are potent chlorinating agents, and chlorine dioxide, a reagent with strong oxidizing activity, is one of the most efficient disinfectants.3) The use of chlorine dioxide as a preoxidant, instead of chlorine, is known to have the benefit of minimizing trihalomethane production following postchlorination.4,5) The solubility of chlorine dioxide is five times that of chlorine and the oxidization activity of chlorine dioxide is about three-fold that of chlorine gas.2) The ClO2 radical is a powerful one-electron oxidant, possessing a redox potential of 936 mV,6) and is known for its ability to oxidize both inorganic and organic species.6,7) Chlorine dioxide also is known for its anti-bacterial and anti-viral properties.7) Chlorine dioxide is capable of triggering the denaturation of enzymes and proteins.8) ClO2 destroys the anabolic pathways of protein and thus kills microorganisms, including bacteria, viruses, and fungi. MA-T (α or γ; A2-care, Co., Ltd., Tokyo), a commercially available disinfectant, is a stable and mild ClO2-generating reagent. MA-T contains sodium chlorite, in combination with one of two kinds of cationic detergents that serves as the Lewis acid catalyzing the generation of ClO2 (the Lewis acidity of both were (α: LUMO (Lowest Unoccupied Molecular Orbital) = -4.12 eV) and (γ: LUMO = -4.02), measured according to the method of reference,9) in unpublished observation), in a buffer stabilizing the solution at a neutral pH. Notably, ClO2 is not detected in MA-T during storage or before use. Live bacteria, the targets of this disinfectant, would induce the production of ClO2 by MA-T. The mechanism by which this chlorine dioxide-generating disinfectant, MA-T, destroys bacteria is of great interest, but is currently unclear. In this paper, we report data indicating that one of the targets of MA-T is the respiratory chain of bacteria.