Antimicrobial activity of quaternary ammonium salts: structure-activity relationship

Compounds with antimicrobial activity have gained much attention in research due to the outbreak of coronavirus disease 2019 (COVID-19). Quaternary ammonium salts (QASs) are an emerging group of antibacterial agents that are used as disinfectants. Many studies have been carried out involving the applications of QASs as antifouling agents for the inhibition of biofilm growth on medical implants and antibacterials on surfaces and in an aquatic environment. In investigating the antibacterial activity of QASs, we addressed the structure-activity relationship and the physicochemical factors. This review is focused on the fine-tuning of the chemical structures of QASs for their applications as wide antibacterial agents.