Table 2.

MICs of antimicrobial agents determined by microdilution for ESBL- or AmpC-producing strains of K. pneumoniae at an inoculum of 105 or 107 CFU/ml

StrainPlasmidEnzymeMIC (μg/ml) at the indicated inoculum (CFU/ml)a:
FOX, 105FEPPIRIPMMEMCIP, 105
105107105107105107105107
143098-3b pMG257SHV-564128>256128>25622228
C1No ESBL128120.5211118
C1-T6pMG226TEM-612832>25664>25612128
C1-T10pMG223TEM-10648>25632>25614218
C1-T12pMG224TEM-1212864>256128>25611118
C1-T26pMG225TEM-2612816>25632>25612128
C1-S2pMG229SHV-2128>256>256256>256416448
C1-S3pUD18SHV-312816>25616>25622224
C1-S5pMG257SHV-5c 64128>256128>25622228
C1-AC233pMG233AmpC>2561>25648646416168
C1-AC245pMG245AmpC>2561>256432326416164
C1-AC248pMG248AmpC>2562>2568>25632644168
C1-AC252pMG252AmpC>25623216>256122432
NEDH-1d pMG258SHV-264>256>256>256>25622220.5
C2No ESBL640.25≤0.50.50.5120.2510.5
C2-S2pMG258SHV-2c 64>256>256>256>25622120.5
C2-AC248pMG248AmpC>25683264128646416160.5
C2-AC250pMG250AmpC>25621616321632480.5
C2-AC252pMG252AmpC>2564>3232>320.520.524
  • a Abbreviations: FOX, cefoxitin; IPM, imipenem; MEM, meropenem; FEP, cefepime; PIR, cefpirome; CIP, ciprofloxacin.

  • b Parental strain of strain C1.

  • c Presumptive identification based on pI.

  • d Parental strain of strain C2.