Table 2.

MICs of β-lactams for E. coli MG-1,E. coli JM109 harboring recombinant plasmids pRLT1 and pRLT50, and reference strain E. coli JM109

Antibiotic(s)MIC (μg/ml) for:
E. coli MG-1aE. coli JM109 (pRLT1)bE. coli JM109 (pRLT50)cE. coli JM109
Amoxicillin>512>512>5122
Amoxicillin-Clad 1288–162561
Ticarcillin>512>512>5122
Ticarcillin-Cla25642562
Piperacillin256165121
Piperacillin-Cla42641
Cephalothin1281282564
Cephalothin-Cla4444
Cefamandole323232–640.5
Cefuroxime641288<2
Cefuroxime-Cla444<2
Cefoxitin4844
Cefoxitin-Cla4422
Ceftazidime25625610.25
Ceftazidime-Cla0.250.2510.25
Cefotaxime220.120.06
Cefotaxime-Cla0.060.060.060.06
Cefepime110.120.06
Cefepime-Cla0.030.060.030.06
Ceftriaxone240.120.06
Moxalactam0.250.120.120.12
Moxalactam-Cla0.250.120.120.25
Aztreonam32320.250.12
Aztreonam-Cla0.120.120.250.06
Imipenem0.250.250.120.12
  • a E. coli MG-1 produces VEB-1 along with a TEM-1 penicillinase.

  • b E. coli JM109 harboring recombinant plasmid pRLT1 produced the VEB-1 β-lactamase.

  • c E. coli JM109 harboring recombinant plasmid pRLT50 produced the TEM-1 β-lactamase.

  • d Cla, clavulanic acid at fixed concentration of 2 μg/ml.