Abstract
An AmpC-type beta-lactamase conferring high-level resistance to expanded-spectrum cephalosporins and monobactams was characterized from an Acinetobacter baumannii clinical isolate. This class C beta-lactamase (named ADC-33) possessed a Pro210Arg substitution together with a duplication of an Ala residue at position 215 (inside the Omega-loop) compared to a reference AmpC cephalosporinase from A. baumannii. ADC-33 hydrolyzed ceftazidime, cefepime, and aztreonam at high levels, which allows the classification of this enzyme as an extended-spectrum AmpC (ESAC). Site-directed mutagenesis confirmed the role of both substitutions in its ESAC property.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Acinetobacter baumannii / drug effects*
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Acinetobacter baumannii / enzymology*
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Acinetobacter baumannii / genetics
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Amino Acid Sequence
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Amino Acid Substitution
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Anti-Bacterial Agents / pharmacology*
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Aztreonam / pharmacology
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Bacterial Proteins / genetics
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Bacterial Proteins / metabolism
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Cefepime
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Ceftazidime / pharmacology
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Cephalosporin Resistance
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Cephalosporinase / genetics
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Cephalosporinase / metabolism*
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Cephalosporins / pharmacology*
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Humans
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Microbial Sensitivity Tests
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Molecular Sequence Data
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Monobactams / pharmacology*
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Mutagenesis, Site-Directed
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beta-Lactamases / genetics
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beta-Lactamases / metabolism
Substances
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Anti-Bacterial Agents
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Bacterial Proteins
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Cephalosporins
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Monobactams
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Cefepime
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Ceftazidime
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Cephalosporinase
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AmpC beta-lactamases
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beta-Lactamases
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Aztreonam