The Antibacterial Action of Surface Active Cations

Abstract

The antibacterial action of a technical mixture of higher alkyl dimethyl benzyl ammonium chlorides and of cetyl pyrid-inium bromide on Staphylococcus aureus, Eberthella ty-phosa and Escherichia coli was reversed by detoxicating the treated organisms with 1-1.5 equivalent of Duponol PC (Na dodecyl sulfate), provided the germicide was applied for only a brief period and in a relatively low conc. which was, however, higher than the killing conc. detd. by the F.D.A. method. The antibacterial action of dodecyl dimethyl benzyl ammonium chloride is reduced by the addition of 20-25% of the hexadecyl or octadecyl homologs, thus indicating the subtractive effect of relatively harmless competitive compounds. The bacteriostatic action of acri-flavine on E. coli was reversed by the addition of Duponol PC.