TABLE 2.
Tentative microbiological criteria for ciprofloxacin, moxifloxacin, levofloxacin, and nalidixic acid for microdilution and disk diffusion tests for H. influenzae with and without amino acid changes in QRDRs of GyrA and ParC
| Quinolone | MIC (μg/ml) criteria (correlated zone diameter [mm])
|
% Test error
|
||||
|---|---|---|---|---|---|---|
| No amino acid changes | None or one amino acid change in QRDR of GyrA | Two amino acid changes in QRDRs of GyrA and ParC | Very major | Major | Minor | |
| Ciprofloxacin | ≤0.06 (≥39) | 0.12-0.25 (31-38) | ≥0.5 (≤30) | 0.0 | 0.0 | 3.2 |
| Levofloxacin | ≤0.03 (≥34) | 0.06-0.25 (30-33) | ≥0.5 (≤29) | 0.0 | 0.0 | 8.5 |
| Moxifloxacin | ≤0.03 (≥31) | 0.06-0.25 (27-31) | ≥0.5 (≤26) | 0.0 | 0.0 | 5.0 |
| Nalidixic acid | ≤2.0 (≥32) | 4.0-16 (19-31) | ≥32 (≤18) | 0.0 | 0.0 | 0.0 |