TABLE 2.

Antibiotic susceptibility of the strains constructed to test the substrate selectivity of the MexEF-OprN pump^a

Strain	Plasmid	Pump component(s) expressed	MIC (μg/ml)
			NFLX	OFLX	CP	TET	GM	KM	EM	NOV	CAZ	CPZ	CPR	CZOP	CAR	AZT	MPM	IPM	TMP
PAO4290		ABM	0.78	0.78	100	25	3.13	3.13	400	1,600	1.56	6.25	3.13	0.78	25	3.13	0.39	1.56	200
TNP077			0.1	0.05	3.13	0.39	0.39	3.13	25	100	0.39	1.56	1.56	0.39	3.13	0.2	0.2	1.56	12.5
TNP0773	pMMB67EH		0.1	0.05	3.13	0.39	0.39	3.13	12.5	100	0.78	25	3.13	0.39	>800	0.2	0.2	1.56	12.5
TNP0771	pMEXAB-OPRM1	ABM	3.13	3.13	800	50	3.13	3.13	400	1600	3.13	25	6.25	1.56	>800	25	1.56	1.56	>1,600
TNP0775	pMEXEF-OPRN1	EFN	3.13	3.13	1,600	3.13	0.39	3.13	12.5	100	0.39	25	1.56	0.39	>800	0.2	0.2	1.56	>1,600
TNP0776	pVLT33		0.1	0.1	3.13	0.39	0.39	400	12.5	100	0.39	3.13	3.13	0.39	6.25	0.2	0.39	1.56	12.5
TNP0777	pMEXEF-OPRN-KM1	EFN	6.25	3.13	1,600	1.56	0.39	400	12.5	100	0.39	3.13	1.56	0.39	3.13	0.2	0.2	1.56	>1,600
PAO4009		ABM	0.39	0.78	50	25	3.13	100	400	800	0.78	6.25	3.13	0.78	25	3.13	0.78	0.78	200
KH4014a		ABM, EFN	12.5	12.5	1,600	25	1.56	25	200	400	0.78	3.13	0.78	0.39	12.5	1.56	0.78	3.13	>1,600

^aMueller-Hinton agar contained 2 mM IPTG. Abbreviations: NFLX, norfloxacin; OFLX, ofloxacin; CP, chloramphenicol; TET, tetracycline; GM, gentamicin; KM, kanamycin; EM, erythromycin; NOV, novobiocin; CAZ, ceftazidime; CPZ, cefoperazone; CPR, cefpirome; CZOP, cefozopran; CAR, carbenicillin; AZT, aztreonam; MPM, meropenem; IPM, imipenem; TMP, trimethoprim. Pump components expressed are shown as varying combinations of the following subunits: A, MexA; B, MexB; E, MexE; F, MexF; M, OprM; and N, OprN.