TABLE 5.
Accuracy of updated 2010 susceptibility breakpoints in differentiating between carbapenem-susceptible groups (WT strains and ESBL producers) and groups with decreased carbapenem susceptibility (ESBL/Omp and KPC-Kp isolates)
| Group (n) | Method | No. of susceptible isolates/no. of resistant isolates |
|||
|---|---|---|---|---|---|
| Imipenem | Meropenem | Ertapenem | Doripenem | ||
| WT (43) | BMDa | 43/0 | 43/0 | 43/0 | 43/0 |
| Etestb | 43/0 | 43/0 | 43/0 | 43/0 | |
| DDc | 43/0 | 43/0 | 43/0 | 43/0 | |
| ESBL producers (42) | BMDa | 40/2 | 40/2 | 28/14 | 40/2 |
| Etestb | 40/2 | 40/2 | 30/12 | 42/0 | |
| DDc | 42/0 | 40/2 | 30/12 | 40/2 | |
| ESBL/Omp strains (18) | BMDa | 4/14 | 2/16 | 0/18 | 0/18 |
| Etestb | 5/13 | 1/17 | 0/18 | 5/13 | |
| DDc | 7/11 | 1/17 | 0/18 | 1/17 | |
| KPC-Kp isolates (42) | BMDa | 0/42 | 0/42 | 0/42 | 0/42 |
| Etestb | 10/32 | 4/38 | 1/41 | 2/40 | |
| DDc | 0/42 | 0/42 | 0/42 | 0/42 | |
a
Based on MIC breakpoints of ≤1 μg/ml (susceptible) and ≥2 μg/ml (nonsusceptible) for IPM, MEM, and DOR and ≤0.25 μg/ml (susceptible) and ≥0.5 μg/ml (nonsusceptible) for ERT.
b
Based on MIC breakpoints of ≤1 μg/ml (susceptible) and ≥1.5 μg/ml (nonsusceptible) for IPM, MEM, and DOR and ≤0.25 μg/ml (susceptible) and ≥0.38 μg/ml (nonsusceptible) for ERT.
c
Based on disk diffusion breakpoints of ≥23 mm (susceptible) and ≤22 mm (nonsusceptible) for IPM, MEM, ERT, and DOR.