TABLE 1.

MICs of antibiotics for cells carrying mutant MexB

Strain	MIC (mg/liter)a
	Aztreonam	Novobiocin	Nalidixic acid	Chloramphenicol
Wild-type PAO4290	6.25	>1,600	100	50
PAO4290ΔB	0.39	100	25	12.5
PAO4290ΔB/pMMB67EH	0.39	100	25	12.5
PAO4290ΔB/pMEXB1	6.25	>1,600	100	100
PAO4290ΔB/pMEX-D407N	0.39	100	25	12.5
PAO4290ΔB/pMEX-D407A	0.39	100	25	12.5
PAO4290ΔB/pMEX-D407K	0.39	100	25	12.5
PAO4290ΔB/pMEX-D407E	0.78	200	25	12.5∼25
PAO4290ΔB/pMEX-D408N	0.39	100	25	12.5
PAO4290ΔB/pMEX-D408A	0.39	100	25	12.5
PAO4290ΔB/pMEX-D408K	0.39	100	25	12.5
PAO4290ΔB/pMEX-D408E	3.12	400	50	25∼50
PAO4290ΔB/pMEX-K939A	0.39	100	12.5	12.5
PAO4290ΔB/pMEX-K939E	0.39	100	12.5	12.5
PAO4290ΔB/pMEX-K939D	0.39	50	12.5	12.5
PAO4290ΔB/pMEX-K939R	6.25	1,600	100	50
PAO4290ΔB/pMEX-D407E/D408E	0.39	100	25	12.5
PAO4290ΔB/pMEX-D407E/D408E/K939R	0.78	100∼200	25	12.5∼25
PAO4290ΔB/pMEX-D407E/K939R	0.78	200	25	25
PAO4290ΔB/pMEX-D407K/K939D	0.39	100	25	12.5
PAO4290ΔB/pMEX-D407A/K939A	0.39	100	25	12.5
PAO4290ΔB/pMEX-D408E/K939R	3.12	400	50∼100	25∼50
PAO4290ΔB/pMEX-D408K/K939D	0.39	100	12.5	12.5
PAO4290ΔB/pMEX-D408A/K939A	0.39	100	12.5	12.5
PAO4290ΔB/pMEX-D407R/D408R	0.39	100	25	12.5
PAO4290ΔB/pMEX-K342A	6.25	1,600	100	50
PAO4290ΔB/pMEX-K342R	6.25	1,600	100	100
PAO4290ΔB/pMEX-K342E	6.25	1,600	100	100
PAO4290ΔB/pMEX-E346Q	6.25	1,600	100	50
PAO4290ΔB/pMEX-E346A	6.25	1,600	100	100
PAO4290ΔB/pMEX-E346D	6.25	1,600	100	100
PAO4290ΔB/pMEX-E346K	1.56	400	50	25
PAO4290ΔB/pMEX-E346K/K342E	3.12	400∼800	50∼100	25∼50

^aMICs of antibiotics were determined by the agar dilution method, in which the plate was incubated for 18 h at 37°C. The MICs shown are representative results of several repeated experiments.