Properties and expression of a multidrug efflux pump AcrAB-KocC from Klebsiella pneumoniae

Dai Wei Li, Motoyasu Onishi, Takanori Kishino, Taira Matsuo, Wakano Ogawa, Teruo Kuroda, Tomofusa Tsuchiya

Research output: Contribution to journalArticlepeer-review

28 Citations (Scopus)


We previously reported that we had cloned genes responsible for multidrug resistance from the chromosomal DNA of Klebsiella pneumoniae MGH78578 using a drug-hypersusceptible Escherichia coli strain as a host. One of the recombinant plasmids pETV6 conferred resistance to host cells against a wide range of antimicrobial agents, dyes and detergents. It was revealed that this plasmid carried the acrBKp gene and a part of the acrAKp gene coding for a multidrug efflux pump belonging to the RND family. We cloned the whole acrAKpBKp operon of K. pneumoniae and characterized the pump. The AcrAB pump utilized TolC as an outer membrane component in cells of E. coli. Elevated energy-dependent efflux of ethidium was observed with cells possessing AcrAKp BKp-TolC. We cloned a gene coding for an ortholog of TolC from chromosomal DNA of K. pneumoniae, and designated it kocC. It seems that the AcrAKKpBKp-KocC complex functions as a potent multidrug efflux pump in K. pneumoniae. We observed a higher level of expression of acrAKp in K. pneumoniae MGH78578, a multidrug resistant strain, compared with ATCC10031, a drug susceptible strain.

Original languageEnglish
Pages (from-to)577-582
Number of pages6
JournalBiological and Pharmaceutical Bulletin
Issue number4
Publication statusPublished - Apr 2008
Externally publishedYes


  • AcrAB-KocC
  • Drug resistance
  • Klebsiella pneumoniae
  • Multidrug efflux pump
  • Resistance nodulation cell-division

ASJC Scopus subject areas

  • Pharmacology
  • Pharmaceutical Science


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