Table 2

Results of tests of cefpodoxime with and without the concomitant presence of amoxicillin-clavulanate (Amox-Clav) by broth dilution and disk diffusion testing

ESBL group (no. of isolates)MIC tested aloneCefpodoxime MIC tested with Amox-Clava% susceptibleb% detected by disk approximationc
CefpodoximeAmox-Clavd
MIC50eMIC90fRangeMIC50MIC90RangeMIC50MIC90Range
CTX-M (28)g>32>3216–>3216324–>320.258≤0.06–>3289.3100
SHV (17)h>32>322–>3232>324–>320.5>32≤0.06–>3258.8100
CTX-M + SHV (3)i>32>32>3232>3216–>321>32≤0.06–>3266.7100
  • a Cefpodoxime was tested in standard 2-fold dilution series in the presence of a fixed concentration of 8 μg/ml amoxicillin and 4 μg/ml clavulanate.

  • b Susceptible to cefpodoxime at ≤2 μg/ml when tested in the presence of amoxicillin-clavulanate.

  • c Percent of those susceptible to the drug combination by MIC that were detected by disk approximation testing.

  • d Activity of the amoxicillin-clavulanate combination expressed as the amoxicillin component.

  • e MIC50, MIC required to inhibit 50% of isolates.

  • f MIC90, MIC required to inhibit 90% of isolates.

  • g The following isolates were included: 20 E. coli, 7 Klebsiella spp., and 1 Enterobacter spp.

  • h The following isolates were included: 4 E. coli, 11 Klebsiella spp., and 2 Enterobacter spp.

  • i Included 1 E. coli isolate and 2 Klebsiella spp. isolates.