Use of a small‐scale, portable test chamber for determining the bactericidal efficacy of aerosolized glycol formulations

Abstract

This study aimed to understand the efficacy and mechanisms of action of an aerosolised glycol-ethanol formulations against bacteria. We validated a small scale in-house test chamber to determine the microbicidal efficacy of four aerosolized formulations combining dipropylene glycol and ethanol against Staphylococcus aureus and Escherichia coli embedded in alginate. The aerosolised glycol/ethanol formulation decreased bacterial viability by 3 Log10 and was more efficacious than an ethanol only control formulation. Electron microscopic examination indicated extensive structural damage in both bacteria, and membrane damage was confirmed with potassium release in S. aureus and DNA release in E. coli. The development of a small test chamber facilitated the measurement of the microbicidal efficacy and experiments to understand the mechanism of action of an aerosolised microbicidal formulation.