TABLE 1.

MICs of antibiotics to P. aeruginosa PAO1 in the presence of polyamines, EDTA, and PMBN

Antibiotic	MIC (μg/ml) in presence ofa:
	No compound	Spd	Spn	Put	Cad	EDTA	PMBN	Arg
Ampicillin	>1,024	64	64	128	128	32	16	>1,024
Azlocillin	4	1	1	2	2	1	1	4
Aztreonam	4	0.5	0.5	1	0.5	1	0.5	4
Carbenicillin	64	4	4	16	16	4	2	64
Cefoperazone	4	2	2	2	2	1	1	4
Ceftazidime	2	0.5	0.5	1	0.5	0.5	0.25	2
Ceftriaxone	16	0.25	0.25	4	0.25	2	0.5	16
Cephaloridine	>1,024	1,024	1,024	1,024	1,024	256	128	>1,024
Cephalothin	>1,024	1,024	1,024	1,024	1,024	256	128	>1,024
Cloxacillin	>1,024	1,024	1,024	1,024	1,024	1,024	1,024	>1,024
Moxalactam	8	0.25	0.25	2	0.25	1	1	8
Penicillin G	>1,024	512	512	512	512	128	128	>1,024
Piperacillin	8	2	2	2	2	2	2	8
Ticarcillin	16	2	2	4	0.5	4	4	16
Chloramphenicol	128	32	32	64	64	8	2	128
Nalidixic acid	128	64	64	64	64	64	4	128
Trimethoprim	256	128	64	128	128	32	4	256
Erythromycin	128	128	64	128	128	32	1	128
Novobiocin	>1,024	>1,024	>1,024	>1,024	>1,024	512	256	>1,024
Fusidic acid	1,024	1,024	1,024	1,024	1,024	128	2	1,024

^aMIC measurements in MH broth were repeated three times with identical results. Compound concentrations were as follows: 20 mM spermidine (Spd), putrescine (Put), cadaverine (Cad), and arginine (Arg); 1 mM spermine (Spn) and EDTA; and 1 μg/ml PMBN.