High-Level Expression of Chromosomally Encoded SHV-1 β-Lactamase and an Outer Membrane Protein Change Confer Resistance to Ceftazidime and Piperacillin- Tazobactam in a Clinical Isolate of Klebsiella pneumoniae

Abstract excerpt

We describe Klebsiella pneumoniae 15571, a clinical isolate resistant to ceftazidime MIC = 32 microg/ml) and piperacillin-tazobactam (MICs = 1,024 and 128 microg/ml). K. pneumoniae 15571 expresses a single beta-lactamase with a pI of 7.6. However, when cloned in a high-copy-number vector in Escherichia coli, this bla(SHV-1) gene did not confer resistance to ceftazidime, a spectrum consistent with the nucleotide...