TABLE 3

MICs against blaKPC-3 deletion mutants and E. coli transformantsa

KPC-3 variantDescriptionMIC range (μg/ml)
Ceftazidime-avibactamCeftazidimeMeropenemPiperacillin-tazobactamCefepimeCeftriaxoneAztreonam
Wild-typeClinical isolates 1-A, 2-A, 3-A2–4256–51232–128>512>128>128>256
Clinical isolate with blaKPC deletionb0.5256≤0.12516–32832>256
E. coli with blaKPC-containing plasmid from clinical isolatec1128225632>128>256
E. coli with pET30a plasmid into which blaKPC was clonedd≤0.25–0.564–1282–8>512>128>128>256
D179Y, T243 MClinical isolates 1-B, 1-C256>5120.25–0.5>51216328
Clinical isolate with blaKPC deletionb≤0.25128≤0.125128842
E. coli with blaKPC-containing plasmid from clinical isolatec64256≤0.1256483264
E. coli with pET30a plasmid into which blaKPC was clonedd64≥512≤0.1252–42–84–82–4
D179YClinical isolates 2-C, 3-B, 3-C64 to >256≥5120.125–4256 to >5124–164–164–8
Clinical isolate with blaKPC deletionb≤0.25256≤0.12532–1281632>256
E. coli with blaKPC-containing plasmid from clinical isolatec16128≤0.12516442
E. coli with pET30a plasmid into which blaKPC was clonedd864≤0.1251142
V240GClinical isolate 2-B32>5128>512>128>128>256
Clinical isolate with blaKPC deletionb0.5128≤0.12532832>256
E. coli with blaKPC-containing plasmid from clinical isolatec4512125632>128>256
E. coli with pET30a plasmid into which blaKPC was clonedd22561128128>128>256
  • a Boldface rows represent baseline carbapenem-resistant K. pneumoniae isolates.

  • b blaKPC deletions were performed for a representative clinical isolate with each KPC-3 variant.

  • c IncFIA pBK30683-like plasmids were extracted from representative clinical isolates and transferred into E. coli DH10B.

  • d blaKPC genes from representative clinical isolates were cloned into a pET30a expression vector plasmid, which was transferred into E. coli DH5α. Ceftazidime-avibactam, ceftazidime, and meropenem MICs against E. coli DH5α carrying pET30a without blaKPC genes were ≤0.25, ≤0.5, and ≤0.125 μg/ml, respectively.