TABLE 1.

Drug resistance of E. coli cells harboring pTrc plasmids carrying putative response regulator ORFs

Drug	No gene (0.01, 0.1, 1)	MIC (μg/ml) for strain carrying gene, with indicated IPTG concn (mM)a
		evgA			baeR		cpxRb		dcuR
		0.01	0.1	1	0.01, 0.1	1	0.01	0.1, 1	0.01	0.1	1
Erythromycin	3.13	12.5	25	3.13	3.13	3.13	3.13	3.13	3.13	6.25	6.25
Kanamycin	3.13	3.13	3.13	1.56	3.13	3.13	3.13	12.5	3.13	3.13	3.13
Fosfomycin	1.56/0.78d	1.56	0.78	0.78	1.56/0.78d	0.78	1.56	0.78	1.56	0.78	0.78
Doxorubicin	3.13	100	25	3.13	3.13	3.13	3.13	3.13	3.13	3.13	3.13
Novobiocin	0.78	3.13	0.78	0.78	6.25	6.25	0.78	3.13	0.78	3.13	3.13
Crystal violet	0.78	3.13	1.56	0.78	0.78	0.78	0.78	0.78	0.78	0.78	1.56
Ethidium bromide	25	50	50	25	25	25	12.5	12.5	25	25	25
Rhodamine 6G	6.25	100	25	3.13	6.25	6.25	6.25	6.25	6.25	6.25	6.25
Methyl viologen	100	100	50	50	100	100	100	100	100	100	100
TPP	6.25	25	25	6.25	6.25	6.25	3.13	6.25	6.25	6.25	6.25
Benzalkonium	3.13	25	12.5	3.13	3.13	3.13	3.13	3.13	3.13	3.13	3.13
SDS	50	400	50	50	100	100	50	50	50	100	100
Deoxycholate	1,250	>40,000	1,250	1,250	>40,000	1,250	1,250	>40,000	1,250	20,000	20,000

^aValues in boldface are larger than values for the control strain KAM3 harboring pTrc99A. IPTG at 0.01, 0.1, or 1 mM was added to the agar plates. pTrcarcA, pTrcatoC, pTrcb2381, pTrcbasR, pTrccheB, pTrccheY, pTrccreB, pTrcglnG, pTrchydG, pTrcphoB, pTrcphoP, pTrcrssB, pTrcuhpA, pTrcuvrY, pTrcyfhA, pTrcygiX, and pTrcylcA did not affect the MICs. The MICs of chloramphenicol, tetracycline, minocycline, nalidixic acid, norfloxacin, enoxacin, rifampin, polymyxin B, acriflavine, and carbonyl cyanide m-chlorophenylhydrazone did not change.

^bpTrccpxR conferred amikacin resistance (MIC of 1.56 μg/ml for KAM3 versus 6.25 μg/ml for KAM3/pTrccpxR).

^cThe growth of the KAM3 strain carrying pTrcfimZ was inhibited with 1,250 μg of deoxycholate per ml; however, the growth recovered with 10,000 to 40,000 μg/ml.

^dThe fosfomycin MIC for host and baeR cells was 1.56 μg/ml with 0.01 and 1 mM IPTG and 0.78 μg/ml with 0.1 mM IPTG.