Evaluation of a bipolar ionization device in inactivation of antimicrobial-resistant bacteria, yeast, Aspergillus spp. and human coronavirus

BACKGROUND: The efficacy of bipolar ionization in the healthcare setting has yet to be proven. A major limitation of studies sponsored by industry has been the assessment of efficiency within test chambers in which ozone levels are not adequately controlled. AIM: To assess the effectiveness of bipolar ionization against antimicrobial-resistant bacteria, fungi and human coronavirus within a controlled test chamber designed to mitigate the effect of ozone. METHODS: Bacteria- and fungi-inoculated gauze pads, and human coronavirus 229E-inoculated stainless steel plates were placed within the vicinity of the AIO-2 bipolar ionizer and left at room temperature (2 h for coronavirus and 4 h for bacteria and fungi). FINDINGS: Four hours of exposure to bipolar ionization showed a 1.23–4.76 log reduction, corresponding to a 94.2–>99.9% colony-forming units/gauze reduction, in Clostridioides difficile, Klebsiella pneumoniae carbapenemase-producing K. pneumoniae, meticillin-resistant Staphylococcus aureus and multi-drug-resistant S. aureus. A 1.2 log 50% tissue culture infectious dose reduction in human coronavirus was observed after 2 h. CONCLUSION: The assessment of bipolar ionization systems merits further investigation as an infection control measure.