Table 1.

MICs of β-lactams for strains testeda

Antibiotic(s)bMIC (μg/ml)
KPO787C600(pEKPO787)HB101(pEKPO787D1)C600(pEKPB657)HB101(pUC19)HB101
Amoxicillin>256>256>256>256>2564
Amoxicillin + CLA>2566464882
Piperacillin>256>25616642561
Piperacillin + TZB1286484321
Cephalothin>256>256>256>2562562
Cefuroxime>256>256>256>25680.5
Cefaclor>256>256>256>25640.5
Cefotaxime64323280.130.06
Cefotaxime + CLA3232320.030.030.03
Ceftazidime>256>256>2561280.250.13
Ceftazidime + CLA>2562562560.130.030.03
Ceftriaxone643232160.130.13
Ceftriaxone + CLA3232160.030.030.03
Cefoxitin>256>256>256442
Aztreonam256640.13640.130.13
Aztreonam + CLA0.130.030.030.030.030.03
Imipenem8220.130.130.13
Imipenem + CLA2220.030.030.03
Meropenem16210.130.130.06
Meropenem + CLA210.50.030.030.03
  • a K. pneumoniae KPO787 andE. coli C600(pEKPO787) expressed IMP-7, SHV-12, and TEM-1.E. coli HB101(pEKPO787D1), C600(pEKPB657), and HB101(pUC19) expressed IMP-7, SHV-12, and TEM-1, respectively.

  • b CLA, clavulanic acid at a fixed concentration of 2 μg/ml; TZB, tazobactam at a fixed concentration of 4 μg/ml.