Table 9

Single-step resistance frequency for isolates of E. coli and K. pneumoniae

AntibioticMIC (μg/ml)Concn selected (MIC multiple)Resistance frequencya
E. coli OXA-1, SHV-5
    AN336514-fold1.3 × 10−7
10-fold7.5 × 10−8
    Ceftazidime>164-foldND
10-foldND
    Meropenem14-foldND
10-foldND
K. pneumoniae ATCC 13883
    AN336514-fold8.1 × 10−7
10-fold6.1 × 10−8
    Ceftazidime0.254-fold∼10−6
10-fold∼10−6
    Meropenem0.064-fold<2.5 × 10−9
10-fold<2.5 × 10−9
K. pneumoniae ATCC 51503
    AN336514-fold5.3 × 10−8
10-fold3.8 × 10−8
    Ceftazidime>164-foldND
10-foldND
    Meropenem0.54-fold4.8 × 10−7
10-fold<3.7 × 10−9
  • a ND, not determined.