Positive and negative ions (PAIs and NAIs, respectively) generated by air ionizers curb indoor spread of airborne pathogens through cellular oxidative damage. Thus, here, we asked whether ion exposure of Staphylococcus aureus and Escherichia coli bacteria-either plated on agar or trapped in air filters-would affect their viability and whether this effect would be influenced by variations in bacterial type and load, action area, distance from the ion generator, exposure time, or filter type. We selected these two vegetative bacterium species because, besides being representative of Gram-positive and Gram-negative strains, respectively, they are widely recognized as the two most common airborne pathogens. We observed a robust ion inhibitory effect on the viability of free bacteria regardless of the experimental condition employed. Specifically, 12-h ion exposure of plated S. aureus and E. coli, at either 5 cm or 10 cm from the ion source, reduced bacterial viability by ∼95% and 70%, respectively. Furthermore, 3-h ion exposure was sufficient to reduce the viability of both bacterial species trapped in filters. Our results showing a strong antibacterial activity of PAI and NAI under all experimental conditions tested further support the use of air ionizers for preventing and/or containing airborne infection in domestic and nondomestic settings.

Positive and Negative Ions Potently Inhibit the Viability of Airborne Gram-Positive and Gram-Negative Bacteria [V. Allizond is the corresponding author, G.Banche and A.M.Cuffini are co-last authors]

Sara Comini
First
;
Narcisa Mandras;Maria Rita Iannantuoni;Francesca Menotti;Valeria Allizond
;
Giuliana Banche
Co-last
;
Anna Maria Cuffini
Co-last
2021

Abstract

Positive and negative ions (PAIs and NAIs, respectively) generated by air ionizers curb indoor spread of airborne pathogens through cellular oxidative damage. Thus, here, we asked whether ion exposure of Staphylococcus aureus and Escherichia coli bacteria-either plated on agar or trapped in air filters-would affect their viability and whether this effect would be influenced by variations in bacterial type and load, action area, distance from the ion generator, exposure time, or filter type. We selected these two vegetative bacterium species because, besides being representative of Gram-positive and Gram-negative strains, respectively, they are widely recognized as the two most common airborne pathogens. We observed a robust ion inhibitory effect on the viability of free bacteria regardless of the experimental condition employed. Specifically, 12-h ion exposure of plated S. aureus and E. coli, at either 5 cm or 10 cm from the ion source, reduced bacterial viability by ∼95% and 70%, respectively. Furthermore, 3-h ion exposure was sufficient to reduce the viability of both bacterial species trapped in filters. Our results showing a strong antibacterial activity of PAI and NAI under all experimental conditions tested further support the use of air ionizers for preventing and/or containing airborne infection in domestic and nondomestic settings.
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air filters, air ionizer, antibacterial activity, Escherichia coli, Staphylococcus aureus
Sara Comini, Narcisa Mandras, Maria Rita Iannantuoni, Francesca Menotti, Andrea Giuseppe Musumeci, Giorgia Piersigilli, Valeria Allizond, Giuliana Banche, Anna Maria Cuffini
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2318/1818299
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