PaP1, a Broad-Spectrum Lysin-Derived Cationic Peptide to Treat Polymicrobial Skin Infections

Abstract

Most skin infections, including those complicating burns, are polymicrobial involving multiple causative bacteria. Add to this the fact that many of these organisms may be antibiotic-resistant, and a simple skin lesion or burn could soon become life-threatening. Membrane-acting cationic peptides from Gram-negative bacteriophage lysins can potentially aid in addressing the urgent need for alternative therapeutics. Such peptides natively constitute an amphipathic region within the structural composition of these lysins and function to permit outer membrane permeabilization in Gram-negative bacteria when added externally. This consequently allows the lysin to access and degrade the peptidoglycan substrate, resulting in rapid hypotonic lysis and bacterial death. When separated from the lysin, some of these cationic peptides kill sensitive bacteria more effectively than the native molecule via both outer and cytoplasmic membrane disruption. In this study, we evaluated the antibacterial properties of a modified cationic peptide from the broad-acting lysin PlyPa01. The peptide, termed PaP1, exhibited potent in vitro bactericidal activity toward numerous high priority Gram-positive and Gram-negative pathogens, including all the antibiotic-resistant ESKAPE pathogens. Both planktonic and biofilm-state bacteria were sensitive to the peptide, and results from time-kill assays revealed PaP1 kills bacteria on contact. The peptide was bactericidal over a wide temperature and pH range and could withstand autoclaving without loss of activity. However, high salt concentrations and complex matrices were found to be largely inhibitory, limiting its use to topical applications. Importantly, unlike other membrane-acting antimicrobials, PaP1 lacked cytotoxicity toward human cells. Results from a murine burn wound infection model using methicillin-resistant Staphylococcus aureus or multidrug-resistant Pseudomonas aeruginosa validated the in vivo antibacterial efficacy of PaP1. In these studies, the peptide enhanced the potency of topical antibiotics used clinically for treating chronic wound infections. Despite the necessity for additional preclinical drug development, the collective data from our study support PaP1 as a potential broad-spectrum monotherapy or adjunctive therapy for the topical treatment of polymicrobial infections and provide a foundation for engineering future lysin-derived peptides with improved antibacterial properties.

ESKtides: a comprehensive database and mining method for ESKAPE phage-derived antimicrobial peptides

“…Comparative analysis with CAMPR4 showcased advantages in our platform, particularly in PGH-based peptide performance prediction. For example, the studies ( 37 , 38 ) described that P. aeruginosa peptides (X1–X4 and PaP1-1 from PGHs) show low antibacterial activity in experiment, but CAMPR4 was determined to be high activity, our platform was determined the low activity, which is more fitted with experiment result. This case study underscores our platform’s efficacy in peptide identification and streamlining candidates for subsequent biological experiments.…”

“…( 15 ), has more advantages in predicting peptides mined based on PGHs. Previous studies ( 37 , 38 ) described that P. aeruginosa peptides (X1–X4 and PaP1-1 from PGHs) showed low antibacterial activity in experiments, in contrast to the high activity predicted by CAMPR4. ESKtides showed more closely with experimental results by indicating low activity for these peptides.…”

Alginate Gel Encapsulated with Enzybiotics Cocktail Is Effective against Multispecies Biofilms

“…Thus, we have shown that, at high concentrations, both lysins demonstrate cross-specificity and are able to act on various species regardless of their Gram-staining status and the PG structure. We assume that the antimicrobial activity of these enzymes could be caused not only by the catalytic activity but also by other interactions of the enzymes with receptors of bacterial cells, for example, due to the membrane-permeabilizing ability of specific lysin domains [11,16,17].…”

“…Since alginates are polyanionic polymers, the electrostatic interactions comprise a significant driving force of the protein-polysaccharides complex formation. At the same time, peptidoglycan hydrolases are small proteins often possessing regions with the high positive charge density that can play a functional role in antimicrobial activity [16,17]. Although electrostatic interactions may increase alginate complexation with lysins, they can also affect the antimicrobial properties of the enzymes when encapsulated in a polymer matrix, and this should be monitored.…”

Recent advances to combat ESKAPE pathogens with special reference to essential oils

“…PaP1 is a peptide derived from the PlyPa01 lysin (isolated from a phage infecting P. aeruginosa ) characterized by membrane-acting properties and modified in order to increase the net charge of the peptide, as well as its antibacterial properties. When tested, PaP1 was found active on the ESKAPE pathogens in both monospecies and polymicrobial populations ( A. baumannii , P. aeruginosa and S. aureus ) and eradicates P. aeruginosa mature biofilms in vitro ( Heselpoth et al, 2022 ).…”