Potential novel therapeutic strategies in cystic fibrosis: antimicrobial and anti-biofilm activity of natural and designed α-helical peptides against Staphylococcus aureus, Pseudomonas aeruginosa, and Stenotrophomonas maltophilia

Table 3 In vitro effect of AMP + Tobramycin (TOB) combinations against P. aeruginosa , S. maltophilia , and S. aureus CF strains

Drug combinations	P. aeruginosa			S. maltophilia			S. aureus
	Synergy	Indifference	Antagonism	Synergy	Indifference	Antagonism	Synergy	Indifference	Antagonism
	FICI^a≤ 0.5	0.5 < FICI ≤ 4	FICI > 4	FICI ≤ 0.5	0.5 < FICI ≤ 4	FICI > 4	FICI ≤ 0.5	0.5 < FICI ≤ 4	FICI > 4
BMAP-27 + TOB	0 (0%)	12 (100%)	0 (0%)	0 (0%)	8 (100%)	0 (0%)	1 (100%)^b	0 (0%)^b	0 (0%)^b
BMAP-28 + TOB	0 (0%)	12 (100%)	0 (0%)	0 (0%)	8 (100%)	0 (0%)	0 (0%)^c	1 (100%)^c	0 (0%)^c
P19(9/B) + TOB	0 (0%)	12 (100%)	0 (0%)	0 (0%)	8 (100%)	0 (0%)	1 (33.3%)^d	2 (66.7%)^d	0 (0%)^d

^a Fractional Inhibitory Concentration Index (FICI).
Only isolates exhibiting in-range MIC values were considered for checkerboard titration method: P. aeruginosa (n = 12), S. maltophilia (n = 8), and S. aureus (^b n = 1; ^c n = 1; ^d n = 3).

ISSN: 1471-2180