TABLE 2.

Quinolone MICs for nalidixic acid-susceptible, nalidixic acid-resistant, and ciprofloxacin-resistant Salmonella isolates obtained by the agar dilution method

Antibiotic	MIC (μg/ml) for:
	Nalidixic acid-susceptible isolates (n = 62)			Nalidixic acid-resistant isolates (n = 124)			Ciprofloxacin-resistant isolatesa (n = 5)
	50%	90%	Range	50%	90%	Range
Nalidixic acid	4	8	4-8	512	>1,024	128->1,024	>1,024
Norfloxacin	0.12	0.12	0.12	1	2	0.25-4	>16
Enrofloxacin	0.06	0.06	0.06	0.5	1	0.25-2	>32b
Ciprofloxacin	0.03	0.06	0.03-0.06	0.25	0.5	0.25-2.0	16

^aThe five isolates were Salmonella serovar Typhimurium DT104.

^bDetermined by Etest.