Involvement of outer membrane of Pseudomonas cepacia in aminoglycoside and polymyxin resistance

R. A. Moore, R. E.W. Hancock

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Pseudomonas cepacia was found to be resistant to the outer membrane-permeabilizing effects of aminoglycoside antibiotics, polymyxin B, and EDTA. Permeabilization of P. cepacia to the fluorescent probe 1-N-phenylnaphthylamine was not achieved at concentrations 100- to 1,000-fold above those required to permeabilized Pseudomonas aeruginosa. Furthermore, in contrast to P. aeruginosa cells, intact cells of P. cepacia did not bind the fluorescent probe dansyl-polymyxin. However, purified lipopolysaccharide (LPS) from P. cepacia bound dansyl-polymyxin with approximately the same affinity as did LPS from P. aeruginosa. Also, binding of dansyl-polymyxin to P. cepacia (and P. aeruginosa) LPS was inhibited by polymyxin B, streptomycin, gentamicin, and Mg2+. These data suggest that P. cepacia does not utilize the self-promoted pathway for aminoglycoside uptake and that the outer membrane is arranged in a way that conceals or protects cation-binding sites on LPS which are capable of binding polycations such as aminoglycosides or polymyxin.

Original languageEnglish
Pages (from-to)923-926
Number of pages4
JournalAntimicrobial Agents and Chemotherapy
Issue number6
Publication statusPublished - 1986

ASJC Scopus subject areas

  • Pharmacology
  • Pharmacology (medical)
  • Infectious Diseases

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