A new member of the tripartite multidrug efflux pumps, MexVW-OprM, in Pseudomonas aeruginosa

Yang Li, Takehiko Mima, Yukiko Komori, Yuji Morita, Teruo Kuroda, Tohru Mizushima, Tomofusa Tsuchiya

Research output: Contribution to journalArticlepeer-review

102 Citations (Scopus)


Objectives: Multidrug efflux pumps are thought to be involved in mediating multidrug resistance in Pseudomonas aeruginosa. Here we aim to characterize hitherto uncharacterized multidrug efflux pumps from P. aeruginosa. Materials and methods: We isolated a mutant, YM442, which showed elevated resistance to several antimicrobial agents from P. aeruginosa YM44 lacking four major multidrug efflux pumps, MexAB, MexCD-OprJ, MexEF-OprN and MexXY. We cloned genes responsible for the resistance from chromosomal DNA of YM442 using YM44 as host. Results: We designated the genes mexVW. Introduction of a recombinant plasmid pTAJ2 carrying the mexVW into YM44 cells conferred resistance to fluoroquinolones, tetracycline, chloramphenicol, erythromycin, ethidium bromide and acriflavine. Elevated ethidium bromide extrusion was observed with cells of YM442 and of YM44/pTAJ2. An outer membrane protein OprM was able to cooperate with MexVW. Elevated expression of the mexV gene was observed with YM442 compared with YM44. Conclusions: MexV (membrane fusion protein)-MexW (RND-type membrane protein)-OprM is a tripartite multidrug efflux pump. It is suggested that other outer membrane component(s) could cooperate with MexVW.

Original languageEnglish
Pages (from-to)572-575
Number of pages4
JournalJournal of Antimicrobial Chemotherapy
Issue number4
Publication statusPublished - 2003 Oct 1
Externally publishedYes


  • MexVW
  • Multidrug efflux pump
  • P. aeruginosa
  • RND-type

ASJC Scopus subject areas

  • Pharmacology
  • Microbiology (medical)
  • Infectious Diseases
  • Pharmacology (medical)


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