Mrs. Rebecca Cumming1, Prof. Jean-Yves Maillard1
1Cardiff University, Cardiff, United Kingdom
Biography:
Rebecca Cumming is a research assistant at Cardiff University with a focus on disinfection efficacy and microbial surface interactions. Her research has evaluated disinfectant effectiveness, highlighting how test protocols and material properties influence performance. She has contributed insights into disinfectant mechanisms of action and antimicrobial resistance, supporting improved infection prevention.
Abstract:
Introduction
The COVID-19 pandemic emphasized the need for non-toxic, effective aerosol disinfectants. Although the bactericidal and virucidal efficacy of aerosolised glycols is well-documented, their mechanisms of action, particularly in aerosolized form, remain poorly understood. This study aims to address that gap.
Methods
Droplets of several Gram-positive and gram-negative bacteria were inoculated on stainless-steel (SS) or plastic surfaces and incubated either wet or dried. Surfaces were exposed to dipropylene glycol (DPG) aerosol delivered as a 30-second spray. After 10 minutes contact, surviving bacteria were enumerated. Benzalkonium chloride (BZC, 0.2%) was used as a biocide control.
Results
A greater efficacy against dried inocula of K. pneumoniae and A. baumannii (<1 LR wet vs. >3 LR dry) was observed, suggesting aerosolised DPG enhances desiccation-related membrane damage. Higher efficacy was also observed on plastic compared to SS, likely due to surface hydrophobicity preserving hydration. BZC efficacy remained consistent across the different conditions.
Conclusion
Aerosolized DPG exhibits enhanced bactericidal activity against desiccated Gram-negative bacteria – an effect not previously reported to our knowledge. We propose that glycol aerosols intensify existing structural damage in pathogens, explaining their efficacy against pathogens in aerosols. Electron microscopy and flow cytometry should provide evidence of differential membrane damage.