Table 6.

Synergy of AZM with DJK-5, PMB, and colistin (COL) against P. aeruginosa PAO1 WT, ∆arn, and ∆arn+arn-complemented strain

Strain	Peptide	Media	FICI	Reduction (fold change) in AZM MIC	Reduction (fold change) in peptide MIC
PAO1 WT	DJK-5	MHB	0.75	4	2
		RPMI	0.50	4	4
		RPMI/serum	0.38	8	4
	PMB	MHB	0.75	4	2
		RPMI	1.00	2	2
		RPMI/serum	0.50	4	4
	COL	MHB	0.50	4	4
		RPMI	1.00	2	2
		RPMI/serum	0.50	4	4
PAO1 ∆arn	DJK-5	MHB	0.50	4	4
		RPMI	0.50	4	4
		RPMI/serum	0.38	8	4
	PMB	MHB	0.38	8	4
		RPMI	2.00	4	2
		RPMI/serum	0.50	4	4
	COL	MHB	0.38	8	4
		RPMI	0.63	8	2
		RPMI/serum	0.38	8	4
PAO1 ∆arn+arn	DJK-5	MHB	0.50	4	4
		RPMI	0.50	4	4
		RPMI/serum	0.63	8	2
	PMB	MHB	0.63	8	2
		RPMI	2.00	1	1
		RPMI/serum	0.56	16	2
	COL	MHB	0.63	8	2
		RPMI	0.75	4	2
		RPMI/serum	0.75	4	2

Synergy was measured using checkerboard titration assays in MHB, RPMI + 5% MHB (RPMI), and RPMI + 5% MHB + 20% human serum (RPMI/serum). FICI values (rounded to two decimal places) below 0.5 are highly synergistic (shown by bolded typeface), 0.5 to 1 indicate weak synergy or additive nature, and higher than 1 indicate no synergy or antagonism.