title: Gene cloning and characteristics of the RND-type multidrug efflux pump MuxABC-OpmB possessing two RND components in Pseudomonas aeruginosa.
abstract: muxA-muxB-muxC-opmB (formerly PA2528-PA2527-PA2526-opmB), encoding a putative resistance nodulation cell division (RND)-type multidrug efflux pump system, was cloned from Pseudomonas aeruginosa PAO1. Introduction of muxABC-opmB into P. aeruginosa YM64, a drug-hypersusceptible strain, led to elevated MICs of aztreonam, macrolides, novobiocin and tetracycline. Since muxB and muxC, both of which encode RND components, were essential for function, MuxABC-OpmB is thought to be a drug efflux pump with four components. One novobiocin-resistant mutant, PMX725, isolated from P. aeruginosa PMX7 showed elevated resistance not only to novobiocin but also to aztreonam, macrolides and tetracycline. Increased mRNA expression of muxABC-opmB was observed in the mutant PMX725 compared with the parental strain. Sequencing analysis revealed that a single-nucleotide insertion had occurred in the deduced promoter region for muxABC-opmB in PMX725. In this study, we have characterized the last RND-type multidrug efflux pump predicted from the genome sequence in P. aeruginosa.
authors.affiliation: Department of Molecular Microbiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Tsushima, Kita-ku, Okayama 700-8530, Japan.
authors.forename: Takehiko
authors.initials: T
authors.lastname: Mima
authors.affiliation: Department of Molecular Microbiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Tsushima, Kita-ku, Okayama 700-8530, Japan.
authors.forename: Naoki
authors.initials: N
authors.lastname: Kohira
authors.affiliation: Department of Molecular Microbiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Tsushima, Kita-ku, Okayama 700-8530, Japan.
authors.forename: Yang
authors.initials: Y
authors.lastname: Li
authors.affiliation: Department of Molecular Microbiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Tsushima, Kita-ku, Okayama 700-8530, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Sekiya
authors.affiliation: Department of Molecular Microbiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Tsushima, Kita-ku, Okayama 700-8530, Japan.
authors.forename: Wakano
authors.initials: W
authors.lastname: Ogawa
authors.affiliation: Department of Genome Applied Microbiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Tsushima, Kita-ku, Okayama 700-8530, Japan.|Department of Molecular Microbiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Tsushima, Kita-ku, Okayama 700-8530, Japan.
authors.forename: Teruo
authors.initials: T
authors.lastname: Kuroda
authors.affiliation: Department of Molecular Microbiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Tsushima, Kita-ku, Okayama 700-8530, Japan.
authors.forename: Tomofusa
authors.initials: T
authors.lastname: Tsuchiya
mesh_terms: D001425:Bacterial Outer Membrane Proteins / Q000235:genetics*; D001483:Base Sequence; D003001:Cloning, Molecular; D004269:DNA, Bacterial / Q000235:genetics; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics*; D005798:Genes, Bacterial; D026901:Membrane Transport Proteins / Q000235:genetics*; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D009675:Novobiocin / Q000494:pharmacology; D010957:Plasmids; D011401:Promoter Regions, Genetic; D011550:Pseudomonas aeruginosa / Q000235:genetics*
chemical_list: D001425:Bacterial Outer Membrane Proteins; D004269:DNA, Bacterial; D026901:Membrane Transport Proteins; D009675:Novobiocin