Random Peptide Mixtures as Safe and Effective Antimicrobials against Pseudomonas aeruginosa and MRSA in Mouse Models of Bacteremia and Pneumonia

Abstract

Antibiotic resistance is a daunting challenge in modern medicine, and novel approaches that minimize the emergence of resistant pathogens are desperately needed. Antimicrobial peptides are newer therapeutics that attempt to do this; however, they fall short because of low to moderate antimicrobial activity, low protease stability, susceptibility to resistance development, and high cost of production. The recently developed random peptide mixtures (RPMs) are promising alternatives. RPMs are synthesized by incorporating a defined proportion of two amino acids at each coupling step rather than just one, making them highly variable but still defined in their overall composition, chain length, and stereochemistry. Because RPMs have extreme diversity, it is unlikely that bacteria would be capable of rapidly evolving resistance. However, their efficacy against pathogens in animal models of human infectious diseases remained uncharacterized. Here, we demonstrated that RPMs have strong safety and pharmacokinetic profiles. RPMs rapidly killed both Pseudomonas aeruginosa and Staphylococcus aureus efficiently and disrupted preformed biofilms by both pathogens. Importantly, RPMs were efficacious against both pathogens in mouse models of bacteremia and acute pneumonia. Our results demonstrate that RPMs are potent broad-spectrum therapeutics against antibiotic-resistant pathogens.

Antimicrobial Peptide Combination Can Hinder Resistance Evolution

“…Thus, the RPM contains more than 1 million sequences (2 20 optional sequences in the mixture) of peptides that are all composed of the same two amino acids. RPMs were found to be highly effective against a variety of pathogens, even in vivo ( 34 ). We evolved the bacteria with 20-mer RPM composed of phenylalanine and lysine (FK), which represents a complexed case of peptide combinations.…”

Advances and perspectives for antimicrobial peptide and combinatory therapies

“…In other study was evaluated the RPM cocktail effect (dFDK, LK20, FK20, and FdK peptides) in vitro , and demonstrated that four RPM (5 µg ml −1 each of RPM) in a cocktail (20 µg ml −1 ) were more effective against all 3 A. baumannii isolates tested than single RPM (100 µg ml −1 ), even the single RPM having been the able to capable to eradicate A. baumannii biofilms and inhibited mouse models of infection ( Caraway et al, 2022 ). The results in vitro also However, the single RPM was capable to eradicated A. baumannii biofilms ( Bennett et al, 2021 ; Caraway et al, 2022 ). In addition to increasing the lethality, this may be more efficient from the point of view of the variety of pathogens that a single combination can control ( Geitani et al, 2019 ; Hanson et al, 2019 ; Bechinger et al, 2020 ).…”

“…RPM consist in performed synthetic peptide by incorporation of a defined proportion of two or more amino acids, making RPM extreme diversity. So, it tourn improbably the rapid bacterial resistance ( Bauer et al, 2020 ; Bennett et al, 2021 ). In other study was evaluated the RPM cocktail effect (dFDK, LK20, FK20, and FdK peptides) in vitro , and demonstrated that four RPM (5 µg ml −1 each of RPM) in a cocktail (20 µg ml −1 ) were more effective against all 3 A. baumannii isolates tested than single RPM (100 µg ml −1 ), even the single RPM having been the able to capable to eradicate A. baumannii biofilms and inhibited mouse models of infection ( Caraway et al, 2022 ).…”

Pharmacological Evaluation of Synthetic Dominant-Negative Peptides Derived from the Competence-Stimulating Peptide of Streptococcus pneumoniae

“…Cy7.5-CSP1, Cy7.5-CSP1-E1A, Cy7.5-CSP1-E1A-cyc­(Dap6E10), Cy7.5-CSP2, and Cy7.5-CSP2-E1Ad10 were intravenously (i.v.) administered at 50 μg concentration to CD-1 mice, and the fluorescence outputs were monitored spatiotemporally by using an IVIS SpectrumCT in vivo imaging system (PerkinElmer), as we have previously described, , with excitation/emission values set at the 745/800 nm. Note that although we were successful in labeling CSP2, we encountered issues in solubilizing the Cy7.5-CSP2 analog in the aqueous conditions required for the IVIS studies.…”