Eighteen strains of Klebsiella pneumoniae recently isolated from hospitalized patients were resistant or moderately resistant to oxyimino-cephalosporins (ceftazidime and/or cefotaxime), aztreonam, cefoxitin and all but one were susceptible to imipenem. Analysis of enzymes produced by these clinical isolates revealed a wide pattern of extended-spectrum β-lactamases. All isolates produced one or more β-lactamases that were characterized preliminarily by their isoelectric point. Strains isolated early were from patients in the Intensive Care Unit and produced an ESβ-lactamase with an apparent pI of 7.6, whereas the later isolates were from surgical and medical wards of the same hospital and produced ESβ-lactamases with apparent pI of 8.2 and 8.4, repectively. This suggests the emergence of SHV-5 and MIR-1 β-lactamases in our hospital. Agarose gel electrophoresis of plasmid DNA revealed the presence of a similar plasmid of approximate size 60 Kb in all isolates.
- Aztreonam resistance
- Cefoxitin resistance
- Extended-spectrum β-lactamases
- Klebsiella pneumoniae
- Oxyimino-cephalosporins resistance
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