Abstract Consequent to the coronavirus disease 2019 (COVID-19) pandemic, indoor disinfection using high-pressure sprays has been prioritized. For high-pressure sprays to be effective, particles must be dispersed within a range of 10–30 µm. We had previously developed a novel disinfection system, which employs a portable high-pressure spray of pH-neutral electrolyzed water with hypochlorous acid, consistently generating particles within this size range. The system was validated for efficacy in laboratory settings but not in real-world settings. In this study, we aimed to evaluate its effectiveness in reducing airborne bacterial levels in various indoor environments including a public health center, senior care hospitals, fitness centers, and childcare center. We identified and quantified the bacteria and analyzed their antibiotic resistance profiles. Opportunistic pathogens known for antibiotic resistance, specifically ESKAPE bacteria ( Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa , and Enterobacter species) were focused on. Over a six-month period in 2023, bacterial counts in air samples collected before and after air disinfection reduced significantly (72.9%). The counts that initially exceeded the South Korean regulatory limit of 800 CFU/m 3 at selected facilities decreased to compliant levels. The most common isolate was Micrococcus luteus , followed by Staphylococcus spp., and Bacillus spp. The proportions of bacterial types before and after disinfection were similar. The ESKAPE pathogens constituted 15 of 793 isolates (1.9%), and seven ESKAPE pathogens (5 of 15, 33.3%) exhibited multidrug resistance to three or more antibiotic classes. These findings underscore the necessity for regular air disinfection protocols, especially in settings with vulnerable populations such as the older adults and children, to effectively manage the risks associated with airborne multidrug resistant and opportunistic pathogens.
Bae et al. (Wed,) studied this question.