Azithromycin Exhibits Bactericidal Effects on Pseudomonas aeruginosa through Interaction with the Outer Membrane

• DOI: 10.1128/aac.49.4.1377-1380.2005
• Publication Date: 2005-03-25T19:23:13Z
• Authors: Yoshifumi Imamura; Yasuhito Higashiyama; Kazunori Tomono; Koichi Izumikawa; Katsunori Yanagihara; Hideaki Ohno; Yoshitsugu Miyazaki; Yoichi Hirakata; Yohei Mizuta; Jun-ichi Kadota; Barbara H. Iglewski; Shigeru Kohno
• Keywords: Divalent

The aim of the present study was to elucidate effect macrolide antibiotic azithromycin on Pseudomonas aeruginosa. We studied susceptibility in P. aeruginosa PAO1 using a killing assay. cells at exponential growth phase were resistant azithromycin. In contrast, stationary sensitive divalent cations Mg2+ and Ca2+ inhibited this activity, suggesting that action is mediated by interaction with outer membranes cells, since exist between adjacent lipopolysaccharides (LPSs) stabilize membrane. cation chelator EDTA behaved manner resembling azithromycin; killed more than phase. A 1-N-phenylnaphthylamine assay showed interacted membrane increased its permeability while antagonized action. Our results indicate directly interacts displacement from their binding sites LPS. This explains, least part, effectiveness sub-MICs antibiotics pseudomonal chronic airway infection.