TABLE 2.

Resistance rates of second-step P. aeruginosa mutants derived from first-step nfxB mutant

Concn, × MIC (8 μg/ml)	Mutation rate
1×	>5.4 × 10−9
2×	1.1 × 10−9
4×	5.0 × 10−10
8×	<5.4 × 10−10