TABLE 2.

Polyamine effects on MICs of antibiotics in clinical isolates of P. aeruginosa^a

Strain no.	MIC (μg/ml) for indicated antibiotic and treatment
	Carbenicillin			Chloramphenicol			Ciprofloxacin			Polymyxin B
	None	SpN	SpD	None	SpN	SpD	None	SpN	SpD	None	SpN	SpD
PAO1	64	4	4	128	32	32	0.125	0.25	1	1	4	16
F4980	256	8	16	32	2	2	4	4	2	0.25	0.5	2
F66336	256	8	16	8	0.5	2	0.5	2	1	0.125	0.5	0.5
H4563	>1,024	64	32	16	4	2	128	4	2	0.125	0.5	0.5
M22152	>1,024	64	64	16	2	2	4	4	2	0.5	1	2
M37310	1,024	32	32	16	4	4	2	4	2	0.125	0.5	0.5
M38100A	16	64	32	4	8	4	2	4	8	<0.06	<0.06	<0.06
M38100B	1,024	32	32	16	8	8	32	8	4	16	4	1
T2095	256	8	16	32	4	4	2	4	4	0.125	0.5	0.5
T5177	>1,024	64	64	16	2	2	2	4	2	0.5	1	2
T6268	16	2	4	16	2	2	4	4	4	1	4	4
T15464	>1,024	64	32	32	8	2	2	4	4	0.5	1	2

^aSpermine (SpN; 1 mM) and spermidine (SpD; 20 mM) were used for MIC measurements. These concentrations of polyamines did not affect the growth of clinical isolates.