2026-09-24 英国研究イノベーション機構（UKRI）
＜関連情報＞
- https://www.ukri.org/news/research-reveals-the-science-behind-the-fight-against-infection/
- https://www.sciencedirect.com/science/article/pii/S0021979725012822
グラム陰性菌に対する非イオン性およびカチオン性殺生物剤の組み合わせにおける多面的な作用機序の解明 Unveiling the multifaceted mechanisms of action in nonionic and cationic biocide combinations against Gram-negative bacteria
Mingrui Liao, Kangcheng Shen, Kun Ma, Yao Chen, Peixun Li, Philipp Gutfreund, Xuzhi Hu, Jordan T. Petkov, Jian R. Lu
Journal of Colloid and Interface Science Available online: 14 May 2025
DOI:https://doi.org/10.1016/j.jcis.2025.137891
Abstract
Quaternary ammonium compounds (QACs) combined with nonionic surfactants have been among the most effective disinfectants for over half a century, leveraging QACs’ broad-spectrum antimicrobial activity that targets microbial membranes. However, the specific interactions between QACs and microbial membranes, as well as the role of nonionic surfactants in disinfection, remain unclear. This study investigates these mechanisms using two representative surfactants: the cationic didecyldimethyl ammonium chloride (DDAC) and the nonionic hexaethylene glycol monododecyl ether (C12E6). The antimicrobial activity of these agents, individually and sequentially, was assessed against Gram-negative bacteria through a series of in vitro assays, including outer membrane (OM) permeability, inner membrane (IM) depolarization, and live/dead bacterial imaging. Further insights into membrane interactions were obtained using model lipid bilayers in conjunction with antimicrobial efficacy matrices, FICI (fractional inhibition concentration index), fluorescent liposome leakage, small-angle neutron scattering (SANS), and neutron reflectivity (NR). Results indicate that C12E6 binds to the rough A lipopolysaccharide (RaLPS) head region in the OM, reassembling it into heterogeneous aggregates but with limited penetration to cause IM disruption. Conversely, DDAC induced structural disruptions in both OM and IM, resulting in low inhibitory concentrations and rapid bacterial killing. In mixtures, the C12E6 : DDAC ratio significantly influences antimicrobial efficacy, with higher C12E6 levels inhibiting DDAC’s effective membrane interactions.
