TABLE 4.

Frequencies of appearance of mutant strains by selection with various quinolones

Quinolone	Frequency at the following multiple of the MICa:						MPC (μg/ml)
	1×	2×	4×	8×	16×	32×
Gatifloxacin	<5.9 × 10−10	<5.9 × 10−10	<5.9 × 10−10	<5.9 × 10−10	NDc	ND	1
AM-1147b	<2.4 × 10−9	<2.4 × 10−9	<2.4 × 10−9	<2.4 × 10−9	<2.4 × 10−9	ND	1
AM-1121b	>2.4 × 10−6	>2.4 × 10−6	<2.4 × 10−9	<2.4 × 10−9	<2.4 × 10−9	ND	8
Ciprofloxacinb	>2.4 × 10−6	>2.4 × 10−6	<2.4 × 10−9	<2.4 × 10−9	<2.4 × 10−9	ND	8
Clinafloxacin	<5.9 × 10−10	<5.9 × 10−10	<5.9 × 10−10	<5.9 × 10−10	ND	ND	0.25
Moxifloxacin	<5.9 × 10−10	<5.9 × 10−10	<5.9 × 10−10	<5.9 × 10−10	ND	ND	1
Sparfloxacinb	ND	>2.2 × 10−6	>2.2 × 10−6	>2.2 × 10−6	1.1 × 10−7	<1.1 × 10−9	4
Trovafloxacinb	ND	>2.2 × 10−6	6.2 × 10−8	<1.1 × 10−9	<1.1 × 10−9	<1.1 × 10−9	1
Levofloxacinb	ND	1.5 × 10−7	<1.1 × 10−9	<1.1 × 10−9	<1.1 × 10−9	<1.1 × 10−9	4
Norfloxacinb	ND	2.6 × 10−7	2.2 × 10−9	<1.1 × 10−9	<1.1 × 10−9	<1.1 × 10−9	64

^aThe reproducibility of the frequencies has been confirmed in repeated experiments.

^bFrequencies are from previous studies (5, 7).

^cND, not determined.