. 2004 Oct;48(10):4012–4015. doi: 10.1128/AAC.48.10.4012-4015.2004

TABLE 1.

MICs of nalidixic acid, ciprofloxacin, tetracycline, and chloramphenicol for each group of isolates^b

Class	Genotype or phenotype	No. of isolates	MIC (μg/ml)
			Nalidixic acid					Ciprofloxacin					Tetracycline					Chloramphenicol
			Range	GMM	Mode	MIC₅₀	MIC₉₀^c	Range	GMM	Mode	MIC₅₀	MIC₉₀	Range	GMM	Mode	MIC₅₀	MIC₉₀	Range	GMM	Mode	MIC₅₀	MIC₉₀
A	Nal^s Cip^s	8^a (11)	4-8	7.5	8	8	8	0.03-0.25	0.06	0.03	0.03	0.06	1-256	49.2	2	2	128	4-256	42	16	16	16
B	Nal^r Cip^s	125^a (148)	16-256	223.2	256	256	256	0.03-0.5	0.25	0.25	0.25	0.5	1-256	28.5	1	2	128	2-256	12.7	4	4	32
C	Nal^r Cip^r	14^a (23)	256	256	256	256	256	1-2	1.21	1	1	2	1-32	5.29	4	4	8	4-32	15.14	16	16	32
1	WT gyrA WT parC	20^a (24)	4-256	90.6	256	32	256	0.03-1	0.17	0.12	0.12	0.25	1-256	24.6	8	4	32	1-256	31.4	32	16	32
2	WT gyrA parC	19	8-256	116.6	256	16	256	0.03-0.25	0.11	0.12	0.12	0.25	1-256	33.6	4	4	64	4-32	17.9	16	16	32
3	gyrA WT parC	43^a (74)	128-256	253	256	256	256	0.03-2	0.49	0.25, 0.5	0.5	1	1-256	35.2	1	2	128	4-128	19.1	4	4	16
4	gyrA parC	65	256	256	256	256	256	0.12-2	0.34	0.25	0.25	0.5	1-256	21.3	1	1	128	2-32	5.3	4	4	8
All isolates		147^a (182)	4-256	241.6	256	256	256	0.015-2	0.33	0.25	0.25	0.5	1-256	27.4	1	2	128	2-256	14.5	4	4	32

Excludes serovar Typhimurium isolates DT104 and DT193. Numbers in parentheses include these isolates.

Nal^s, MIC of nalidixic acid ≤8 μg/ml; Nal^r, MIC of nalidixic acid, ≥16 μg/ml; Cip^s, MIC of ciprofloxacin, ≤0.5 μg/ml; Cip^r, MIC of ciprofloxacin, ≥1 μg/ml; gyrA, mutation within QRDR of gyrA; parC, mutation within QRDR of parC; WT, wild type (no mutation within QRDR); GMM, geometric mean.

MIC₉₀, MIC for 90% of strains tested.