Localized Hotspot Management: Hand-Held Phage Aerosols as a Complementary Strategy for Carbapenem-Resistant Acinetobacter baumannii Infection Control in Healthcare Settings

Background: Carbapenem-resistant Acinetobacter baumannii (CRAB) remains a major challenge in healthcare settings due to its persistence on inanimate surfaces and resistance to conventional cleaning methods. Bacteriophages (phages) represent a promising biocontrol option owing to their high specificity and lytic activity. Methods: This study evaluated the use of a personal hand-held vibrating mesh nebulizer (VMN) as a rapid and localized delivery platform for phage aerosols. Using two lytic phages (ϕ2, Podovirus; ϕ11, Myovirus), we assessed phage stability under different storage conditions, viability during VMN operation, and surface decontamination efficacy under varying spray parameters. Results: In saline, both phages showed optimal long-term stability at 4 °C, whereas storage at −20 °C resulted in a progressive reduction in infectivity exceeding 3 logs over the storage period. VMN aerosolization did not compromise viability. A 3 min spray achieved >99.9% surface reduction: ϕ2 was effective at 1 × 107 PFU/mL, whereas ϕ11 required 1 × 108 PFU/mL. Importantly, residual ϕ2 activity persisted for at least 24 h, preventing detectable recolonization under the assay conditions, while ϕ11 protection was limited to 6 h. Conclusions: These findings establish the hand-held sprayer as a practical, low-cost, and flexible approach to deliver viable phage aerosols, providing an effective complement to large-scale disinfection systems and offering a targeted strategy to enhance infection control in healthcare environments.