TABLE 3.

Antibiotic susceptibility of the strains constructed to assign the substrate-selective subunit(s)^a

Strain	Plasmid	Pump component expressed	MIC (μg/ml)
			NFLX	CP	NOV	AZT
TNP070		-BM	0.39	12.5	100	0.2
TNP0703	pMMB67EH	-BM	0.39	12.5	100	0.39
TNP0701	pMEXA1	ABM	0.39	100	1,600	1.56
TNP0705	pMEXE1	EBM	0.39	12.5	100	0.39
TNP071		A-M	0.39	12.5	100	0.2
TNP0713	pMMB67EH	A-M	0.39	12.5	100	0.39
TNP0711	pMEXB1	ABM	0.78	100	1,600	3.13
TNP0715	pMEXF1	AFM	0.39	12.5	50	0.78
TNP072		AB-	0.1	3.13	100	0.2
TNP0723	pMMB67EH	AB-	0.1	3.13	100	0.39
TNP0721	pOPRM1	ABM	0.78	50	200	3.13
TNP0725	pOPRN1	ABN	0.1	3.13	50	0.2
TNP073		--M	0.39	12.5	100	0.2
TNP0733	pMMB67EH	--M	0.39	12.5	100	0.39
TNP0731	pMEXAB1	ABM	0.78	200	1,600	3.13
TNP0735	pMEXEF1	EFM	3.13	1,600	100	0.2

^aMueller-Hinton agar contained 2 mM IPTG. Abbreviations: NFLX, norfloxacin; CP, chloramphenicol; NOV, novobiocin; AZT, aztreonam. Pump components expressed are shown as various combinations of the following subunits: A, MexA; B, MexB; E, MexE; F, MexF; M, OprM; and N, OprN. A hyphen indicates a missing subunit.