The outer membrane of Pseudomonas aeruginosa NCTC 6749 contributes to its tolerance to the essential oil of Melaleuca alternifolia (tea tree oil)

Lett Appl Microbiol. 2000 Apr;30(4):294-7. doi: 10.1046/j.1472-765x.2000.00712.x.


Pseudomonas aeruginosa is less susceptible to the antimicrobial properties of tea tree oil than many bacteria and its tolerance is considered to be due to its outer membrane. Polymyxin B nonapeptide (PMBN), which has no antibacterial action, was used to permeabilize the outer membrane. The addition of PMBN to Ps. aeruginosa NCTC 6749 markedly increased this organism's susceptibility to tea tree oil and to its normally inert hydrocarbons, p-cymene and gamma-terpinene.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anti-Infective Agents, Local / chemistry
  • Anti-Infective Agents, Local / pharmacology*
  • Cell Membrane / drug effects*
  • Cell Membrane Permeability
  • Colony Count, Microbial
  • Drug Resistance, Microbial
  • Microbial Sensitivity Tests
  • Pseudomonas aeruginosa / drug effects*
  • Pseudomonas aeruginosa / growth & development
  • Tea Tree Oil / chemistry
  • Tea Tree Oil / pharmacology*
  • Terpenes / pharmacology


  • Anti-Infective Agents, Local
  • Terpenes
  • Tea Tree Oil