title: Nonionic surfactants enhancing bactericidal activity at their critical micelle concentrations.
abstract: Bactericidal activities of benzalkonium chloride [also known as alkyldimethylbenzylammonium chloride (ADBAC)] containing nonionic surfactants such as methyl ester ethoxylates (MEE) with the alkyl group C8-C14 and oxyethylene (EO) group of average adduct number 3-15 were measured against Escherichia coli and Staphylococcus aureus. Sample solutions containing MEE in the vicinity of the critical micelle concentration exhibited a dramatic decrease in viable bacterial counts. MEE with an alkyl group of C12 and an oxyethylene group of lower adduct number exhibited little viable bacterial counts than those having higher EO adduct numbers. MEE with reduced EO adduct numbers increased fluorescence intensity in E. coli using the viability stain SYTO 9. Our results show that MEE molecules with low EO adduct numbers exhibited bactericidal activity by increasing the permeability of the E. coli cell membrane. Sample solution containing ADBAC and MEE molecules with lower EO adduct numbers also displayed higher zeta potentials. Moreover, ADBAC molecules incorporated into micelles of MEE with lower EO adduct numbers were adsorbed onto the surface of E. coli, which augmented bactericidal activity.
authors.affiliation: Fabric-care Research Laboratories, Research & Development Headquarters, Lion Corporation.
authors.forename: Seiichi
authors.initials: S
authors.lastname: Tobe
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Majima
authors.forename: Hirohiko
authors.initials: H
authors.lastname: Tadenuma
authors.forename: Tomonari
authors.initials: T
authors.lastname: Suekuni
authors.forename: Kenichi
authors.initials: K
authors.lastname: Sakai
authors.forename: Hideki
authors.initials: H
authors.lastname: Sakai
authors.forename: Masahiko
authors.initials: M
authors.lastname: Abe
mesh_terms: D058491:Bacterial Load / Q000187:drug effects; D001548:Benzalkonium Compounds / Q000737:chemistry / Q000494:pharmacology*; D002463:Cell Membrane Permeability / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004926:Escherichia coli / Q000166:cytology / Q000187:drug effects*; D005026:Ethylene Glycols / Q000737:chemistry; D008823:Micelles; D012996:Solutions; D013211:Staphylococcus aureus / Q000166:cytology / Q000187:drug effects*; D013501:Surface-Active Agents / Q000737:chemistry / Q000494:pharmacology*
chemical_list: D001548:Benzalkonium Compounds; D005026:Ethylene Glycols; D008823:Micelles; D012996:Solutions; D013501:Surface-Active Agents