The antibacterial potency and antibacterial mechanism of a commercially available surface-anchoring quaternary ammonium salt (SAQAS)-based biocide in vitro

Abstract

Aims To determine the antimicrobial potency of a surface‐anchored quaternary ammonium salt (SAQAS)‐based biocide during in vitro wet and dry fomite assays and to determine the mechanism of killing bacteria on the surface. Methods and Results Wet and dry fomite assays were established in vitro for a commercially available biocide (SAQAS‐A) applied to glass and low‐density polyethylene (LDPE) surfaces. Both wet and dry fomite tests showed the active killing of Gram‐positive and Gram‐negative bacteria but not endospores. Assays measuring membrane permeability (ATP and DNA release), bacterial membrane potential and bacterial ROS production were correlated with the time‐to‐kill profiles to show SAQAS‐A activity in suspension and applied to a surface. Conclusions SAQAS‐A is an effective biocide against model strains of vegetative bacteria. The killing mechanism for SAQAS‐A observed minimal membrane depolarization, a surge in ROS production and assessment of membrane permeability supported the puncture of cells in both suspension and surface attachment, leading to cell death. Significance and Impact of the study SAQAS represents effective surface biocides against single challenges with bacteria through a mechanical killing ability that supports real‐world application if their durability can be demonstrated to maintain residual activity.

Quaternary ammonium disinfectants and antiseptics: tolerance, resistance and potential impact on antibiotic resistance

“… Longitudinal studies of the level of QAC accumulation on surfaces repeatedly disinfected with QAC-containing disinfectants and the pathogens recovered from such surfaces may provide data regarding whether or not sub-inhibitory QAC concentrations on surfaces may promote QAC resistance or antibiotic resistance, as noted in some laboratory-based adaptive experiments. Data are needed regarding the tolerance and resistance of newer QAC compounds, such as bis- and tris-QACs and polymeric QACs, where other moieties such as organosilanes, an oxazoline homopolymer, or silver are attached to mono- or bis-QACs [ 137 – 139 ]. Additional field studies are needed to establish the frequency with which in-use solutions of dilutable QAC-based disinfectants are contaminated.…”

“…Data are needed regarding the tolerance and resistance of newer QAC compounds, such as bis- and tris-QACs and polymeric QACs, where other moieties such as organosilanes, an oxazoline homopolymer, or silver are attached to mono- or bis-QACs [ 137 – 139 ].…”

Antimicrobial Coatings: Reviewing Options for Healthcare Applications

“…[122]. The biocide 3-(trimethoxysilyl)propyldimethyloctadecyl ammonium chloride, an organosilicon quaternary ammonium compound (Si-QAC) [122,123], is anchored by the Si-QAC silane group that condenses with free hydroxyl groups on the surface and stabilizes by intermolecular siloxane (Si-O-Si) linkages [124,125]. The antimicrobial mechanism is reliant on the quaternary amine (N+ atom) that attracts the negatively charged microbes onto the needle-like C18 structure of the hydrophobic chain, which leads to the puncture of the bacterial cell envelope and events that cause cell death [117].…”