Table 4.

Kirby-Bauer disk diffusion assay for selected quinolones

StrainRelevant genotypeZone diameter (mm)a
NorOfloxCiproLomNal
PAO1Wild type282031237
2547PAO1 mutant201227137
25482547 mutant191026117
35802547Δ(amrB)281836247
  • a Disk diameter is 6 mm. Disk content (in μg/ml) and resistance and sensitivity ranges (R and S, respectively; also in μg/ml) for the drugs tested were as follows: for norfloxacin (Nor), disk content = 10, R ≤ 12, and S ≥ 17; for ofloxacin (Oflox), disk content = 5, R ≤ 12, and S ≥ 16; for ciprofloxacin (Cipro), disk content = 5, R ≤ 15, and S ≥ 21; for lomefloxacin (Lom), disk content = 10, R ≤ 18, and S ≥ 22; and for nalidixic acid (Nal), disk content = 30, R ≤ 13, and S ≥ 19.