TABLE 2.

MICs of antibiotics for E. coli Lo, transconjugant E. coli J53/pQR1, and E. coli J53 Az

Antibiotic(s)MIC (μg/ml)
E. coli LoaE. coli J53/pQR1E. coli J53
Nalidixic acid>256324
Ofloxacin410.12
Ciprofloxacin10.250.01
Moxifloxacin20.50.03
Sparfloxacin410.01
Rifampin>256328
Chloramphenicol32324
Gentamicin1680.12
Tobramycin128640.12
Streptomycin>256>2562
Amikacin1680.25
Sulfamethoxazole>512>5120.12
Trimethoprim>512>5120.12
Tetracycline>6411
Amoxicillin>512>5124
Amoxicillin-CLAb128324
Ticarcillin>512>5124
Ticarcillin-CLA25644
Piperacillin128162
Piperacillin-TZBc421
Cephalothin1281288
Cefoxitin422
Cefotaxime440.06
Ceftazidime2562560.06
Ceftazidime + CLA0.250.250.06
Aztreonam32320.06
Cefepime110.01
Imipenem0.250.250.06
  • a E. coli Lo and E. coli J53/pQR1 contained the qnr-positive plasmid that also harbored the blaVEB-1 gene.

  • b CLA, clavulanic acid at 2 μg/ml.

  • c TZB, tazobactam at 4 μg/ml.