Abstract
Of 26 tigecycline-nonsusceptible Klebsiella pneumoniae (TNSKP) clinical isolates, 25 had nonsynonymous mutations in ramR and/or acrR (23 in ramR and 10 in acrR). Eight TNSKP isolates possessed overexpression of ramA, acrB, rarA, and oqxB simultaneously, while 8 and 1 TNSKP strains had upregulation of ramA and acrB and of rarA and oqxB, respectively. Thus, resistance mechanisms of 9 TNSKP isolates cannot be explained by the present pathways. This study underscores the role of RamA in TNSKP and suggests the presence of novel tigecycline resistance mechanisms.
Copyright © 2014, American Society for Microbiology. All Rights Reserved.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Anti-Bacterial Agents / pharmacology
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Drug Resistance, Multiple, Bacterial / genetics
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Humans
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Klebsiella Infections / drug therapy
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Klebsiella Infections / microbiology
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Klebsiella pneumoniae / drug effects*
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Klebsiella pneumoniae / genetics*
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Klebsiella pneumoniae / isolation & purification
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Membrane Transport Proteins / genetics*
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Microbial Sensitivity Tests
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Minocycline / analogs & derivatives*
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Minocycline / pharmacology
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Multidrug Resistance-Associated Proteins / genetics*
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Tigecycline
Substances
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AcrR protein, Klebsiella pneumoniae
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Anti-Bacterial Agents
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Membrane Transport Proteins
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Multidrug Resistance-Associated Proteins
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Tigecycline
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Minocycline