Table 6.

Therapeutic Index values for the RRWQWR-based peptides against the ATCC strains of HCAI-relevant bacteria.

Peptide	Attribute	aHmax		Gram positive							Gram negative
			MIC (μM)				gGm	hFold	iTherapeutic index		MIC (μM)				gGm	hFold	iTherapeutic index
		(%)	(μM)	b29212-cS	d25923-cS	e33591-fR			MHC/MIC	jFold	k13883-cS	l700603-fR	m10145-cS	n27853-fR			MHC/MIC	jFold
LfcinB (20–25)	Monomer	7.1	25.0	>200.0	>200.0	>200.0					>200.0	>200.0	>200.0	>200.0
PLS	Palindromic	24.8	100.0	25.6	34.9	25.0	28.2	9.0	3.6	0.1	30.7	26.2	99.7	107.2	54.1	4.1	1.8	0.2
LfcinB (17–31)	Lfc B reference peptide	6.6	25.0	34.3	>200.0	50.0	414.4	13.2	0.6	0.0	>200.0	>200.0	111.7	99.6	105.5	8.1	0.2	0.0
LfcinB (20–25)2	Dimeric	5.6	100.0	13.1	3.0	24.1	9.8	3.1	10.2	0.3	9.0	7.3	29.1	34.8	16.1	1.2	6.2	0.8
LfcinB (20–25)4	Tetrameric	49.1	100.0	3.1	1.7	5.9	3.1	1.0	31.8	1.0	12.0	6.2	18.1	21.7	13.1	1.0	7.6	1.0

^aH_max: Maximum Hemolytic Activity of the indicated peptide against human erythrocytes after 2 h of treatment at 37°C.

^b29212: Enterococcus faecalis.

^cS: sensitive strain.

^d25923: Staphylococcus aureus.

^e33591: Staphylococcus aureus.

^fR: resistant strain.

^gGM: geometric mean of MIC₅₀ values from all three Gram-positive or Gram-negative bacterial ATCC strains in the table.

^hFold: Calculated as (GM for the indicated peptide)/(GM for the tetrameric peptide).

ⁱTherapeutic Index: H_max/GM for the peptides against the Gram-positive or Gram-negative bacteria studied here. A larger value correlates to greater antimicrobial specificity.

^jFold: Calculated as (TI for the indicated peptide)/(TI for the tetrameric peptide).

^k13883: Klebsiella pneumonia.

^l700603: Klebsiella pneumoniae.

^m10145: Pseudomonass aeruginosa.

ⁿ27853: Pseudomonass aeruginosa.