TABLE 1.

Minimum inhibitory concentration (MIC) and fractional inhibitory concentration index (FICI) in vitro susceptibility tests.

Strain	MIC - enrofloxacin (mg/L)	MIC - cefquinome (mg/L)	FICI	MIC—(cefquinome/enrofloxacin 0.5 × MIC) (mg/L)
ATCC 25922 a	0.06	0.06	—	—
ATCC 700603 b	64	32	0.33	1
ZJ42 b	0.13	0.13	0.75	0.06
CLS2 b	2	0.13	0.75	0.03
ZJ42-1.5s c	1	0.13	0.63	0.02

^a E. coli.

^b K. pneumoniae.

^c ZJ42 derivative. Total and ZJ42-1.5s strains were induced from the in vitro dynamic model.