TABLE 1.

Single-step resistance rates in 13 methicillin-resistant S. aureus strains exposed to ciprofloxacin (cipro) or trovafloxacin (trova)

Genotype	Cipro MIC (μg/ml)	Trova MIC (μg/ml)	Inoculum (CFU/ml)	Resistance rate
				Cipro, 4× MIC	Trova, 4× MIC	Cipro, 8× MIC	Trova, 8× MIC
A	1	0.125	5.6 × 108	1.6 × 10−7	1.1 × 10−7	6.3 × 10−8	7.3 × 10−8
B	0.25	0.0625	6.0 × 109	7.5 × 10−8	<6.0 × 10−9	<6.0 × 10−9	<6.0 × 10−9
C	0.25	0.0625	3.8 × 109	2.1 × 10−8	<3.8 × 10−9	<3.8 × 10−9	<3.8 × 10−9
D	0.5	0.0313	4.6 × 108	3.1 × 10−6	<4.6 × 10−8	2.2 × 10−9	<4.6 × 10−8
E	0.125	0.0625	7.8 × 108	6.6 × 10−7	<7.8 × 10−8	<7.8 × 10−8	<7.8 × 10−8
F	0.25	0.0625	1.2 × 1010	2.3 × 10−8	3.3 × 10−10	<1.2 × 10−10	<1.2 × 10−10
G	0.5	0.0313	8.4 × 108	1.9 × 10−6	<8.4 × 10−8	1.2 × 10−9	<8.4 × 10−8
H	0.5	0.0625	2.5 × 109	6.4 × 10−7	<2.5 × 10−9	1.2 × 10−9	<2.5 × 10−9
I	0.25	0.0625	4.4 × 109	5.3 × 10−8	1.6 × 10−9	<4.4 × 10−9	<4.4 × 10−9
J	0.25	0.0625	8.0 × 109	5.8 × 10−8	1.2 × 10−9	<8.0 × 10−9	<8.0 × 10−9
K	0.125	0.125	1.9 × 109	1.0 × 10−6	<1.9 × 10−9	<1.9 × 10−9	<1.9 × 10−9
L	0.5	0.0625	9.0 × 108	1.0 × 10−6	<9.0 × 10−8	1.3 × 10−8	<9.0 × 10−8
M	0.25	0.0625	7.8 × 109	1.6 × 10−7	<7.8 × 10−9	<7.8 × 10−9	<7.8 × 10−9