TABLE 1.

MICs of efflux-related antibiotics against wild-type and recombinant strains

Antibiotic	MIC (μg/mL)
	Ec wt	EcΔmdfA	EcΔmdfA-tac	EcΔmdfA-tac-mdfA when BBR added to medium at:
				0 μg/mL	2 μg/mL	10 μg/mL	20 μg/mL	50 μg/mL
Tetracycline	0.625	0.625	0.625	1.25	1.25	1.25	1.25	0.625
Azithromycin	0.625	0.3125	0.625	0.625	0.625	0.625	0.3125	0.3125
Ciprofloxacin	0.004	0.002	0.004	0.032	0.032	0.016	0.008	0.004
Rifampicin	12.5	12.5	12.5	12.5	12.5	12.5	6.25	6.25
Roxithromycin	0.125	0.125	0.125	0.125	0.125	0.125	0.125	0.0625
Streptomycin	0.75	0.75	0.75	0.75	0.75	0.75	0.375	0.375
Nalidixic acid	2	2	2	2	2	2	2	1
Ampicillin	1	1	1	1	1	0.5	0.5	0.25