Table 2. In vitro activity of 15 antimicrobial agents against 248 FQ-resistant bacteremia E. coli isolates.

Antibiotica	MIC (μg/mL)			% Susceptibility
	Range	MIC50	MIC90	S	I	R
Ampicillinb	—	—	—	6.0	1.2	92.8
Ampicillin-sulbactamb	—	—	—	42.0	17.0	41.0
Ceftazidime	0.06–>256	1	256	63.7	1.6	34.7
Cefepime	<0.03–>256	0.12	4	91.5	3.2	5.3
Cefotaxime	<0.03–>256	0.25	64	59.3	1.6	39.1
Cefoxitin	0.12–>256	8	256	54.0	1.6	44.4
Imipenem	0.12–>256	0.25	0.5	96.0	2.8	1.2
Meropenem	<0.03–>128	<0.03	0.06	98.8	0	1.2
Amikacin	1–>256	4	8	98.0	0.4	1.6
Gentamicinb	—	—	—	54.0	3.6	42.4
Kanamycin	2–>256	16	>256	68.1	5.6	26.3
Tetracycline	1–>256	128	256	26.2	0.4	73.4
Fosfomycin	0.25–>256	1	2	99.6	0	0.4
Ciprofloxacin	0.12–>256	32	128	0	1.6	98.4
Levofloxacin	4–128	16	64	0	3.6	96.4

MIC_50/90, minimum inhibitory concentration for 50% and 90% of the isolates, respectively; S, susceptible; I, intermediate resistant; R, resistant.

^aOne isolate was resistant to tigecycline, and all isolates were susceptible to colistin.

^bAntimicrobial susceptibilities of ampicillin, ampicillin-sulbactam, and gentamicin were determined by the disk diffusion method.