TABLE 2.

MICs of different pump substrates for AcrB mutants of E. coli 3-AG100^a

Mutation	MIC (μg/ml)
	Oxacillin	Doxoru-bicin	Novobi-ocin	Clarithro-mycin	Erythro-mycin	Azithro-mycin	Clin-damycin	Pyronin Y	Linezolid	Mino- cyclin	EtBr	Levo-floxacin	Cipro-floxacin	Hoechst 33342	Propidium iodide	PAβN	Chloram-phenicol	Tetra-cycline	NMP	Spectino-mycin	Genta-micin
F628F wild type (pseudomutation)	>256	>256	512	512	512	64	256	32	512	4	>256	1	0.5	4	>512	>400	8	4	400	32	8
acrB::rpsL-neo	0.5	2	4	4	4	0.5	4	0.5	16	0.125	16	0.06	0.03	0.25	128	50	1	1
F136A	64		64	64	64	16
F178A	32		16	64	128	16			64					0.5
F610A	64	128	32	16	64	2	32	2		0.25	128	0.13	0.06		256	100	2	1
F615A	64		64	32	32
F617A			128
Δ615-617	64		32	128	128					1
F628A	128		128	64		16		8		1				1

^aGentamicin, spectinomycin, and NMP are not substrates of AcrB and were used as controls. For the mutants only the MICs that were ≥4-fold different from the wild-type MIC (F628F pseudomutant) are shown. The substrates and control substances are in order (from left to right) based on the differences in the MICs between the wild type (pseudomutant F628F) and the inactivation mutant (acrB::rpsL-neo).