title: Properties and expression of a multidrug efflux pump AcrAB-KocC from Klebsiella pneumoniae.
abstract: 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 AcrAKpBKp-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.
authors: Department of Molecular Microbiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Tsushima, Okayama 700-8530, Japan.
authors: Dai-Wei
authors: DW
authors: Li
authors: Motoyasu
authors: M
authors: Onishi
authors: Takanori
authors: T
authors: Kishino
authors: Taira
authors: T
authors: Matsuo
authors: Wakano
authors: W
authors: Ogawa
authors: Teruo
authors: T
authors: Kuroda
authors: Tomofusa
authors: T
authors: Tsuchiya
mesh_terms: D002352:Carrier Proteins / Q000737:chemistry* / Q000235:genetics*; D002876:Chromosomes, Bacterial / Q000235:genetics; D003001:Cloning, Molecular; D004269:DNA, Bacterial / Q000235:genetics; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics*; D004926:Escherichia coli / Q000235:genetics; D004996:Ethidium / Q000378:metabolism; D005456:Fluorescent Dyes; D005798:Genes, Bacterial / Q000235:genetics; D007711:Klebsiella pneumoniae / Q000737:chemistry* / Q000187:drug effects / Q000235:genetics*; D008826:Microbial Sensitivity Tests; D010957:Plasmids / Q000235:genetics; D012329:RNA, Bacterial / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D002352:Carrier Proteins; D004269:DNA, Bacterial; D005456:Fluorescent Dyes; D012329:RNA, Bacterial; D004996:Ethidium