TABLE 4.

MICs of antibiotics for clinical isolates and E. coli transformants and recipientsa

Antimicrobial agentbMIC (μg/ml) of antibiotic for E. coli strain:
DH5αINSRA5776 (CTX-M-14 + TEM-1B)DH5α-URA5776 (CTX-M-14)INSRA5905 (CTX-M-15 + TEM-1B)DH5α-URA5905 (CTX-M-15 + TEM-1B)INSRA5924 (CTX-M-32 + TEM-1B)DH5α-URA5924 (CTX-M-32)
Amoxicillin8>4,096>4,096>4,096>4,096>4,096>4,096
Amoxicillin-clavulanic acid*8323264321288
Ticarcillin4>4,096>4,096>4,096>4,096>4,096>4,096
Piperacillin2256256>512512>512512
Piperacillin-tazobactam†1822242
Mecillinam0.12510.52220.5
Cephalothin8>1,0241,024>1,024>1,024>1,024>1,024
Cefuroxime4>256>256>256>256>256>256
Cefoperazone≤0.2525616>51225625664
Ceftriaxone0.033232>51225625664
Ceftriaxone-clavulanic acid*0.060.250.06≤0.016≤0.0160.1250.06
Cefotaxime0.063232512512256128
Cefotaxime-clavulanic acid*0.060.50.060.250.030.1250.06
Ceftazidime0.2521128641616
Ceftazidime-clavulanic acid*0.1250.50.250.250.250.50.25
Aztreonam0.0688128646464
Aztreonam-clavulanic acid*0.060.50.1250.060.060.250.125
Cefepime0.0382328164
Cefoxitin4324164168
Imipenem0.25≤0.060.50.250.250.1250.125
Ciprofloxacin≤0.125256≤0.1251,024≤0.1258≤0.125
Gentamicin≤0.125320.510.2516≤0.125
Trimethoprim≤0.125>64≤0.1250.25≤0.12564≤0.125
  • a E. coli DH5α-URA5776 (harboring CTX-M-14 enzymes), E. coli DH5α-URA5905 (harboring TEM-1B and CTX-M-15 enzymes), and E. coli DH5α-URA5924 (harboring CTX-M-32 enzymes) were transformants of E. coli INSRA5776 (harboring TEM-1B and CTX-M-14 enzymes), E. coli INSRA5905 (harboring TEM-1B and CTX-M-15 enzymes), and E. coli INSRA5924 (harboring TEM-1B and CTX-M-32 enzymes), respectively; E. coli DH5α was the recipient.

  • b *, Clavulanic acid, 2 μg/ml; †, tazobactam, 4 μg/ml.