Table 1

MICs of β-lactams for E. coli clinical isolate and transformantsa

β-Lactam(s)MIC of indicated E. coli isolate
I5 (NDM-4)TOP10 (NDM-4)TOP10 (pNDM-4)TOP10 (pNDM-1)TOP10
Ticarcillin>256>256>256>2564
Ticarcillin + CLA>256>256>256>2564
Piperacillin>256>256>256>2561
Piperacillin + TZB>256>256>256>2561
Cefuroxime>256>256>256>2562
Ceftazidime>256256>256>2560.06
Cefotaxime>256256>256>2560.12
Cefepime>25616>256>2560.06
Cefoxitin>512>2562562564
Aztreonam>2560.250.060.060.12
Imipenem881680.06
Meropenem164880.01
Ertapenem>3281680.01
Doripenem44880.01
  • a Shown are MICs of β-lactams for the E. coli I5 clinical isolate, the transformant E. coli TOP10 harboring the natural plasmid from E. coli I5 and expressing NDM-4, and E. coli TOP10 strains harboring the recombinant plasmid pNDM-4 or pNDM-1 expressing β-lactamase NDM-4 or NDM-1, respectively.