Table 1.

MICs of various β-lactams for strains used in this study

Antibiotic(s)MIC (μg/ml) for:
M. morganii FI-13P. mirabilisFI-14E. coli DH5α(pMN-13)E. coliDH5α(pPM-14)E. coli DH5α
Amoxicillin>64>64>64>644
Amoxicillin-clavulanatea>648884
Piperacillin>256>2562562561
Piperacillin-tazobactamb10.250.511
Cefoxitin>6488168
Cefotaxime>128641616≤0.12
Ceftazidime>6464>64>64≤0.12
Cefepime86424≤0.12
Cefpirome>128>128168≤0.12
Aztreonam>643264320.12
Imipenem240.120.120.12
Meropenem0.030.125≤0.03≤0.03≤0.03
  • a Amoxicillin-clavulanate at a 2:1 ratio.

  • b Tazobactam at a fixed concentration of 4 μg/ml.