The antimicrobial activities of a series of bis-quaternary ammonium compounds

A series of bis-quaternary ammonium compounds（bis-QACs） N,N＇-hevamethylenebis（1-alkyl-4-carbamoyl pyridinium bromide）（4BCAP-6,n）（alkyl chain length,n=8,10,12,14,16 and 18） were synthesized and characterized.Their surface tensions,critical micelle concentrations（CMC）,and antimicrobial activities were evaluated.4BCAP-6,10 exhibited the strongest antimicrobial activities except for that against Proteus vulgari.The activities of 4BCAP-6.n against Escherichia coli zk126 were not significantly influenced by temperature.pH and initial bacteria concentration.These results indicate that bis-QACs exhibit high antimicrobial activity regardless of the environmental conditions.