Table 2.
Drug susceptibility of clinical Escherichia coli isolates (n = 140) used in the study
| Antimicrobial | No. of isolates at the indicated MIC (μg/ml)a |
Range (μg/ml) | MIC50 (μg/ml) | MIC90 (μg/ml) | Resistant isolatesb |
||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| ≤0.5 | 1 | 2 | 4 | 8 | 16 | 32 | 64 | 128 | >128 | No. | Rate (%) | ||||
| Ciprofloxacin | 92 | 8 | 5 | 3 | 5 | 15 | 7 | 5h | ≤0.5 to >64 | ≤0.5 | 32 | 35 | 25 | ||
| Levofloxacin | 99 | 5 | 1 | 5 | 30e | ≤1 to >8 | ≤1 | >8 | 35 | 25 | |||||
| Nalidixic acid | 3 | 26 | 39 | 9 | 4 | 1 | 3 | 2 | 53 | 0.5 to >128 | 4 | >128 | 59 | 42 | |
| Cefepime | 122c | 3 | 3 | 1 | 5 | 6g | ≤0.5 to >32 | ≤1 | 4 | 11 | 7.9 | ||||
| Cefpodoxime | 109 | 9 | 1 | 1 | 2 | 18f | ≤0.5 to >16 | ≤0.5 | >16 | 20 | 14 | ||||
| Cefpodoxime-clavulanic acid | 126 | 7 | 5 | 2 | ≤0.5 to 8 | ≤0.5 | 0.5 | NAi | NAi | ||||||
| Meropenem | 140d | ≤2 | ≤2 | ≤2 | 0 | 0 | |||||||||
a
Vertical lines are shown between resistant and nonresistant isolates.
b
Breakpoint adopted from CLSI recommendations (8).
c
This number represents isolates for which the MIC was ≤1 μg/ml.
d
This number represents isolates for which the MIC was ≤2 μg/ml.
e
This number represents isolates for which the MIC was >8 μg/ml.
f
This number represents isolates for which the MIC was >16 μg/ml.
g
This number represents isolates for which the MIC was >32 μg/ml.
h
This number represents isolates for which the MIC was >64 μg/ml.
i
NA, not applicable.