Table 1.

MICs of β-lactams for clinical isolates M. morganii 1 and 5, E. coli DH10B harboring recombinant plasmid pPON-1, and the E. coli DH10B reference strain

β-LactamMIC (μg/ml)
M. morganii 1E. coliDH10B (pPON-1)E. coli DH10BM. morganii5
Amoxicillin>512>5122512
Amoxicillin + Claa512>5122512
Amoxicillin + Tazb3232232
Ticarcillin86420.12
Ticarcillin + Cla86410.25
Ticarcillin + Taz23210.25
Piperacillin323210.5
Cephalothin>512>5124>512
Cefamandole64321>512
Cefoxitin16128816
Cefepime0.060.060.03<0.06
Cefpirome0.50.060.031
Ceftazidime4160.12<0.06
Ceftazidime + Clav4320.12<0.06
Ceftazidime + Taz0.0620.12<0.06
Cefotaxime440.120.12
Ceftriaxone210.06<0.06
Imipenem10.120.061
Aztreonam110.12<0.06
Moxalactam0.1250.50.25<0.06
  • a Cla, clavulanic acid at a fixed concentration of 2 μg/ml.

  • b Taz, tazobactam at a fixed concentration of 4 μg/ml.