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New Plasmid-Mediated Fluoroquinolone Efflux Pump, QepA ,

New Plasmid-Mediated Fluoroquinolone Efflux Pump, QepA , Found in an Escherichia coli Clinical Isolate. ANTIMICROBIAL AGENTS AND CHEMOTHERAPY, Sept. 2007, p. 3354–3360. 08/01/02 speaker: 郭懿瑩. Fluoroquinolones (FQs) The most common mechanism for resistance to FQs among pathogenic

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New Plasmid-Mediated Fluoroquinolone Efflux Pump, QepA ,

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  1. New Plasmid-Mediated Fluoroquinolone Efflux Pump, QepA, Found in an Escherichia coli Clinical Isolate ANTIMICROBIAL AGENTS AND CHEMOTHERAPY, Sept. 2007, p. 3354–3360 08/01/02 speaker: 郭懿瑩

  2. Fluoroquinolones (FQs) The most common mechanism for resistance to FQs among pathogenic microbes is the mutation of chromosomal genes encoding DNA gyrase and/or topoisomerase IV. Four chromosome-dependent efflux systems responsible for FQ resistance have so far been reported. the resistance nodulation division family the major facilitator superfamily (MFS) the multidrug and toxic compound extrusion family the ATP-binding cassette family In the study, Identified a novel FQ resistance mechanism, QepA, as a plasmid-mediated efflux pump found in an E. coli clinical isolate from Japan.

  3. A novel FQ-resistant gene, qepA, was identified in a plasmid, pHPA, of E. coli C316, and both qepA and rmtB genes were mediated by a probable transposable element flanked by two copies of IS26.

  4. The qepA gene encoded a putative protein, QepA, of 511amino acids. The predicted amino acid sequence of QepA was found to have probably 14 transmembrane segments (TMS) Suggested that QepA belongs to the 14-TMS family transporters of gram-positive Actinomycetales but not those of gram-negative bacteria.

  5. The intracellular accumulation of norfloxacin was decreased in a qepA-expressing E. coli transformant, but this phenomenon was canceled by CCCP (carbonyl cyanide m-chlorophenylhydrazone).

  6. The augmented FQ resistance level acquired by the probable intergeneric transfer of a gene encoding a major facilitator superfamily-type efflux pump from some environmental microbes to E. coli was first identified. Surveillance of the qepA-harboring clinical isolates should be encouraged to minimize further dissemination of the kind of plasmid-dependent FQ resistance determinants among pathogenic microbes.

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