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Peptide dendrimers as “lead compounds” for the treatment of chronic lung infections by Pseudomonas aeruginosa in cystic fibrosis patients: in vitro and in vivo studies

Type of publication Peer-reviewed
Publikationsform Original article (peer-reviewed)
Author Pompilio Arianna, Geminiani Cristina, Mantini Paolo, Siriwardena Thissa N, Di Bonaventura Ivan, Reymond Jean Louis, Di Bonaventura Giovanni,
Project Antimicrobial peptide dendrimers (AMPD) and bicyclic peptides (AMBP) as therapeutic agents against multidrug resistant bacteria
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Original article (peer-reviewed)

Journal Infection and Drug Resistance
Volume (Issue) Volume 11
Page(s) 1767 - 1782
Title of proceedings Infection and Drug Resistance
DOI 10.2147/idr

Open Access

URL http://doi.org/10.2147/IDR
Type of Open Access Publisher (Gold Open Access)

Abstract

Aim: In the present work, the potential of the D-enantiomeric dendrimers dG3KL and dTNS18 was evaluated in relation to tobramycin (Tob), for the development of novel antibacterials to treat Pseudomonas aeruginosa chronic lung infections in patients with cystic fibrosis. Results: The activity of dendrimers against planktonic P. aeruginosa cells was less than Tob against three of the four strains tested (median minimum inhibitory concentration [MIC] 8 vs 1 µg/mL, respectively), but 32-fold higher against the PaPh32 strain isolated at posttransplantation stage. Results from comparative minimum bactericidal concentration/MIC evaluation and time–kill assay suggested a bactericidal mechanism for all test agents. Subinhibitory concentrations of both dendrimers and Tob significantly affected biofilm formation by all strains in a dose-dependent manner, although the PaPh26 strain, isolated during the chronic stage of infection, was particularly susceptible to dendrimers. The activity of dendrimers against preformed P. aeruginosa biofilm was generally comparable to Tob, considering both dispersion and viability of biofilm. Particularly, exposure to the test agent at 10 × MIC caused significant biofilm death (>90%, even to eradication), though with strain-specific differences. Single administration of dendrimers or Tob at 10 × MIC was not toxic in Galleria mellonella wax-moth larvae over 96 hours. However, contrarily to Tob, dendrimers were not protective against systemic infection caused by P. aeruginosa in G. mellonella. Kinetics of P. aeruginosa growth in hemolymph showed that bacterial load increased over time in the presence of dendrimers. Conclusion: Overall, our findings indicated that dG3KL and dTNS18 peptide dendrimers show in vitro activity comparable to Tob against both P. aeruginosa planktonic and biofilm cells at concentrations not toxic in vivo. Further studies are warranted to explore different dosages and to increase the bioavailability of the peptides to solve the lack of protective effect observed in G. mellonella larvae.
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