Table 1.

Antimicrobials used in the study and the tested concentration ranges

Antimicrobialsa	Abbreviation	Breakpoints (μg/mL)			Concentration ranges (μg/mL)
		Sb	I	R
Nalidixic acid	NAL	16	-c	32	2–128
Ciprofloxacin	CIP	0.06	0.12–0.5	1	0.12–16
Enrofloxacin	ENR	0.25	0.5–1	2	0.12–64
Neomycin	NEO	–	–	16	2–32
Gentamicin	GEN	4	8	16	1–64
Streptomycin	STR	32	–	64	2–128
Tetracycline	TET	4	8	16	2–128
Azithromycin	AZM	16	–	32	0.25–64
Amoxicillin/clavulanic acid	AMC	8/4	16/8	32/16	2/1–64/32
Cefoxitin	FOX	8	16	32	1–32
Ceftiofur	XNL	2	4	8	0.5–8
Ampicillin	AMP	8	16	32	2–32
Trimethoprim/sulfamethoxazole	SXT	2/38	–	4/76	0.12/2.38–4/76
Colistin	COL	2	–	4	2–32
Florfenicol	FFN	–	–	32	2–64
Chloramphenicol	CHL	8	16	32	2–64
Tigecycline	TIG	2	4	8	0.12–32
Fosfomycin	FOS	64	128	256	0.25–256

^aSorted based on category of antimicrobials

^bS, sensitivity; I, intermediate resistance; R, resistance

^c-, no standard breakpoint value in related references