Action of Disinfectant Quaternary Ammonium Compounds against Staphylococcus aureus

Abstract

Mode-of-action studies concluded that alkyldimethylbenzylammonium chloride (ADBAC) (a blend of C 12 , C 14 and C 16 alkyl homologues) and didecyldimethylammonium chloride (DDAC) are both membrane-active agents, possessing subtly different modes of action reflecting early cell interactions against Staphylococcus aureus. ADBAC and DDAC exhibited similar MIC behaviors from 0.4 ppm to 1.8 ppm over an inoculum range of 1 ؋ 10 5 to 1 ؋ 10 9 CFU/ml at 35°C. For ADBAC and DDAC, an increased rapidity of killing against S. aureus (final concentration, 2 ؋ 10 9 CFU/ml) was observed at 35°C compared to 25°C. Concentration exponents () for killing were <2.5 for both agents, and temperature influenced the value. Examination of leakage and kill data suggested that a single leakage marker was not indicative of cell death. ADBAC and DDAC possessed Langmuir (L4) and high-affinity (H3/4) uptake isotherms, respectively. ADBAC molecules formed a single monolayer of coverage of cells at the end of primary uptake, and DDAC formed a double monolayer. Rapid cell leakage occurred at bactericidal concentrations, with total depletion of the intracellular potassium and 260-nm-absorbing pools released in this strict order. Autolysis was observed for ADBAC and DDAC at concentrations of 9 g/ml (0.0278 mM and 0.0276 mM, respectively) and above, together with the depletion of approximately 30% of the internal potassium pool. Autolysis contributed to ADBAC and DDAC lethality, although high biocide concentrations may have inhibited autolytic enzyme activity.

Quaternary ammonium compounds in soil: implications for antibiotic resistance development

“…cell membranes and the disruption of membrane integrity, resulting in a leakage of cellular content (Gilbert and Moore 2005;Ioannou et al 2007;Bragg et al 2014). Usually Gram-positive bacteria are more susceptible to QAACs than Gram-negative bacteria due to the lack of the outer membrane, while QAACs are not lethal to bacterial spores and mycobacteria (White and McDermott 2001;Hegstad et al 2010a).…”

Factors Affecting the Phase Behavior and Antimicrobial Activity of Carvacrol Microemulsions

“…This cationic surfactant is a member of a cationic antimi-crobial family called quaternary ammonium compounds which is usually utilized in disinfection. The antimicrobial activity of this surfactant arises from multiple mechanisms 60 . However, the positive charge on CPC is the prime factor for its antimicrobial activity.…”

Quantitative Structure-Activity Relation Study of Quaternary Ammonium Compounds in Pathogen Control: Computational Methods for the Discovery of Food Antimicrobials

“…Generally QACs work as antimicrobials by disrupting cell walls and membranes with hydrophobic tails. These tails pinch off sections in small vesicle-like structures and cause cell leakage that eventually leads to cell death [14][15][16]. CPC follows this same mechanism along with evidence of other more specific targets including transferrin denaturation, ionic channel blocking, and knock-down of halitosis specific transcription factors [14,17,18].…”