Abstract
Four Escherichia coli isolates harboring CTX-M-14, with a single Ala231-->Val substitution compared to CTX-M-9, had three different ribotypes. Cefotaxime resistance was plasmid encoded and conjugatively transferable. Three isolates had the same plasmid restriction enzyme digestion profile, suggesting clonal spread of a resistant plasmid. A high k(cat)/K(m) value for cefotaxime (20.3 microM(-1) s(-1)) but low values for ceftazidime and aztreonam (< 0.02 microM(-1) s(-1)) were observed in hydrolysis assays, indicating resistance to cefotaxime (MIC > or = 64 microg/ml) but susceptibility to ceftazidime (MIC < or = 2 microg/ml).
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Amino Acid Substitution
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Aztreonam / pharmacology
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Cefotaxime / pharmacology
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Ceftazidime / pharmacology
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Cephalosporin Resistance
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Cephalosporins / pharmacology
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Escherichia coli / drug effects
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Escherichia coli / enzymology*
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Escherichia coli / genetics*
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Isoelectric Focusing
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Kinetics
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Microbial Sensitivity Tests
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Monobactams / pharmacology
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Plasmids / genetics*
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RNA, Bacterial / genetics
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Reverse Transcriptase Polymerase Chain Reaction
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Taiwan / epidemiology
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beta-Lactamases / genetics*
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beta-Lactamases / metabolism*
Substances
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Cephalosporins
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Monobactams
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RNA, Bacterial
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Ceftazidime
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beta-lactamase CTX-M-14
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beta-Lactamases
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Aztreonam
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Cefotaxime