TABLE 1

MIC values of antibiotics belonging to different classes for B. cenocepacia K56-2, B. cenocepacia K562dxr, and the complemented mutanta

AntibioticMICs (μg/ml)b against:
Wild typedxr mutantWild type + rhamnosedxr mutant + rhamnosedxr mutant + pDA-dxrWild type + FR900098
Aztreonam>2,048128>2,048>2,048>2,04864
Ceftazidime12881281282568
Cefotaxime2,048642,0482,0481,02416
Meropenem1681616328
Imipenem1283212812812832
Bacitracin32,00016,00032,00032,0008,0008,000
Chloramphenicol321632321632
Ciprofloxacin424444
Erythromycin512512512512512512
Rifampin163232323216
Tetracyclinec84882
Tobramycin256256256256512256
  • a Determined in the presence and absence of rhamnose (0.5%) or FR900098 (250 μM).

  • b Determined in LBB.

  • cThe MIC for tetracycline could not be measured in the dxr mutant expressing dxr in trans, as this plasmid contains a tetracycline resistance marker.