TABLE 4.

Antibiotic resistance of nalB ΔoprM P. aeruginosa K1113 expressing mutant OprM proteins^a

Strain	Plasmid	OprM derivative	OprM expressionb	MIC (μg/ml) ofc:
				CAR	CPZ	CIP	NOR	CAM	NOV
ML5087		Wild type	+	32–64	8	0.1–0.2	0.5–1	64	128
K1112		Wild type	++	512	32	0.8	2	256	>512
K1113			−	1	0.25	0.0125	0.06	2	16
K1113	pVLT31		−	1	0.25	0.0125	0.06	2	16
	pXZL34	Wild type	++	128–256	8	0.2	0.5	64–128	128
	pXZL74	ΔP5-P10	++	128	8	0.4	0.5	128	128
	pXZL88	ΔT28-D37	++	128	8	0.4	0.5	128	64
	pXZL92	ΔR74-I79	++	64	4	0.2	0.5	64	128
	pXZL137	ΔA12-R98	+/−	32–64	2	0.05	0.5	8	16
	pXZL57	ΔS93-G107	+	128	8	0.2	0.5	8	32
	pXZL58	T106-HA-T107	++	256	8	0.2	0.5	32	64
	pXZL75	ΔE125-R131	−	1	0.25	0.0125	0.06	4	16
	pXZL89	ΔA145-A153	−d	1	0.25	0.0125	0.06	8	8
	pXZL90	ΔG199-A209	++	1	0.25	0.0125	0.125	4	8
	pXZL73	ΔA233-G241	+	256	16	0.4	1	64	256
	pXZL133	ΔL257-L264	++	256	16	0.2	1	128	256
	pXZL77	ΔA278-N286	+	1	0.25	0.0125	0.125	4	16
	pXZL91	ΔF317-F326	−d	1	0.25	0.0125	0.125	2	8
	pXZL93	ΔR341-I34	−	1	0.25	0.0125	0.125	4	8
	pXZL76	ΔA445-W450	−	8	1	0.025	0.125	8	16
	pXZL66	ΔL446-A468	−e	1	0.25	0.0125	0.06	8	8
	pXZL67	ΔN451-A468	+	128	8	0.05	0.25	64	256
	pXZL146	C1G	++	128	4	0.1	0.25	64	128
	pXZL86	S2D	+	128	8	0.2	0.5	128	256
	pXZL147	OprF-OprM fusion	++	128	4	0.1	0.5	64	128
	pXZL109	E125K	++	64	4	0.1	0.5	64	128
	pXZL125	L128R	++	128	16	0.2	0.25	128	256
	pXZL104	F129A	+	128	16	0.2	0.5	64	256
	pXZL105	F129Y	+	128	16	0.2	0.5	128	256
	pXZL128	R131E	++	128	16	0.2	0.5	128	256
	pXZL111	E279D	++	128	8	0.1	0.5	64	128
	pXZL108	E279K	+	128	16	0.2	0.5	128	256
	pXZL126	A284F	+	128	8	0.1	0.5	128	128
	pXZL129	A284Y	+	128	16	0.2	0.5	128	256
	pXZL106	L446V	+	128	16	0.2	0.5	128	256
	pXZL110	L446Q	+	128	8	0.2	0.5	128	256
	pXZL112	G448T	+	128	16	0.1	0.5	128	256
	pXZL107	G448A	+	256	8	0.2	0.5	32	256
	pXZL127	W450Y	+	128	8	0.2	0.5	256	128

^aThe antibiotic susceptibility of the nalB ΔoprM strain K1113 harboring plasmids encoding the indicated OprM derivatives was determined as described in Materials and Methods. Susceptibility of the wild type (with respect to MexAB-OprM) strain ML5087 and its nalB derivative K1112 (the parent of K1113) is shown for comparison purposes. 

^bRelative expression (taken from Fig. 2) indicated as ++ (high), + (moderate), +/− (weak), or − (none). 

^cValues in italics represent MICs substantially below that provided by the wild-type OprM protein. CAR, carbenicillin; CPZ, cefoperazone; CIP, ciprofloxacin; NOR, norfloxacin; CAM, chloramphenicol; NOV, novobiocin. 

^dOprM expression detectable in E. coli DH5α. 

^eOprM expression was detectable in cells following induction with IPTG.