Abstract
After two decades of the discovery of plasmid-mediated quinolone resistance (PMQR), three different mechanisms have been associated to this phenomenon: target protection (Qnr proteins, including several families with multiple alleles), active efflux pumps (mainly QepA and OqxAB pumps) and drug modification [AAC(6')-Ib-cr acetyltransferase]. PMQR genes are usually associated with mobile or transposable elements on plasmids, and, in the case of qnr genes, are often incorporated into sul1-type integrons. PMQR has been found in clinical and environmental isolates around the world and appears to be spreading. Although the three PMQR mechanisms alone cause only low-level resistance to quinolones, they can complement other mechanisms of chromosomal resistance to reach clinical resistance level and facilitate the selection of higher-level resistance, raising a threat to the treatment of infections by microorganisms that host these mechanisms.
Keywords:
AAC(6′)-Ib-cr; OqxAB; Plasmid; QepA; Qnr; Quinolone; Resistance.
Copyright © 2016 Elsevier Ltd. All rights reserved.
Publication types
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Review
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Research Support, Non-U.S. Gov't
MeSH terms
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Acetyltransferases / genetics
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Acetyltransferases / metabolism
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Anti-Bacterial Agents / pharmacology
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Bacterial Infections / drug therapy
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Bacterial Infections / microbiology
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Bacterial Proteins / genetics*
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Bacterial Proteins / metabolism
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Chromosomes, Bacterial / chemistry
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Chromosomes, Bacterial / metabolism
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Drug Resistance, Bacterial / genetics*
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Escherichia coli Proteins / genetics
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Escherichia coli Proteins / metabolism
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Gene Expression Regulation, Bacterial*
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Gram-Negative Bacteria / drug effects
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Gram-Negative Bacteria / genetics*
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Gram-Negative Bacteria / metabolism
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Gram-Positive Bacteria / drug effects
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Gram-Positive Bacteria / genetics*
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Gram-Positive Bacteria / metabolism
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Humans
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Microbial Sensitivity Tests
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Plasmids / chemistry
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Plasmids / metabolism*
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Protein Isoforms / genetics
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Protein Isoforms / metabolism
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Quinolones / pharmacology
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Treatment Failure
Substances
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Anti-Bacterial Agents
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Bacterial Proteins
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Escherichia coli Proteins
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Protein Isoforms
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QepA protein, E coli
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Qnr protein, Klebsiella pneumoniae
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Quinolones
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Acetyltransferases
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aminoglycoside N(6')-acetyltransferase