title: Sensitivity of Pseudomonas aeruginosa envelope mutants to alkylbenzyldimethylammonium chlorides.
abstract: A series of stepwise polymyxin-resistant envelope mutants of Pseudomonas aeruginosa was used to test the activity of a homologous series (C10-C18) of alkylbenzyldimethylammonium chlorides. A sterilization kinetics procedure in deionized water was devised to avoid amounts quaternary compound above the critical micelle concentration. In all cases, there was a linear relationship between the logarithm of the rate of change of the colony count with time and the logarithm of the homolog concentration. For all strains, there was a linear relationship between alkyl chain length and the concentration required to reduce the colony count to 10% in 2 hr. The stepwise series of polymyxin-resistant strains increased in resistance to polymyxin about threefold for each step. In general, this increase resulted in a similar increase in resistance to the quaternary compound. It is proposed that death in this system may primarily be a consequence of damage to the outer membrane rather than to the cytoplasmic membrane.
mesh_terms: D000891:Anti-Infective Agents, Local / Q000494:pharmacology*; D002462:Cell Membrane / Q000187:drug effects; D008826:Microbial Sensitivity Tests; D009994:Osmolar Concentration; D011112:Polymyxin B / Q000494:pharmacology; D011550:Pseudomonas aeruginosa / Q000187:drug effects* / Q000235:genetics; D000644:Quaternary Ammonium Compounds / Q000494:pharmacology*; D013329:Structure-Activity Relationship; D013997:Time Factors
chemical_list: D000891:Anti-Infective Agents, Local; D000644:Quaternary Ammonium Compounds; D011112:Polymyxin B