Quaternary ammonium compound stresses induce specific variations in fatty acid composition of Pseudomonas aeruginosa.

The involvement of cell membrane fatty acids in resistance of Pseudomonas aeruginosa to Quaternary Ammonium Compounds (QACs) stresses was investigated. The strain was grown in a medium with increasing concentrations of different biocides: two QACs, and two non-QACs. In the presence of two QACs only, the strain was able to grow with increasing concentrations. During cellular adaptation to QACs, the resistance to the same biocide increased. A principal component analysis was performed with whole of fatty acid compositions which highlighted a specific variation for the cultures in presence of QACs. These modifications gave evidence of the outer membrane involvement in cellular response to the presence of QACs.