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Antimicrobial activity of synthetic cationic peptides and lipopeptides derived from human lactoferricin against Pseudomonas aeruginosa planktonic cultures and biofilms

BACKGROUND: Infections by Pseudomonas aeruginosa constitute a serious health threat because this pathogen –particularly when it forms biofilms – can acquire resistance to the majority of conventional antibiotics. This study evaluated the antimicrobial activity of synthetic peptides based on LF11, an...

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Autores principales: Sánchez-Gómez, Susana, Ferrer-Espada, Raquel, Stewart, Philip S., Pitts, Betsey, Lohner, Karl, Martínez de Tejada, Guillermo
Formato: Online Artículo Texto
Lenguaje:English
Publicado: BioMed Central 2015
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4491869/
https://www.ncbi.nlm.nih.gov/pubmed/26149536
http://dx.doi.org/10.1186/s12866-015-0473-x
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author Sánchez-Gómez, Susana
Ferrer-Espada, Raquel
Stewart, Philip S.
Pitts, Betsey
Lohner, Karl
Martínez de Tejada, Guillermo
author_facet Sánchez-Gómez, Susana
Ferrer-Espada, Raquel
Stewart, Philip S.
Pitts, Betsey
Lohner, Karl
Martínez de Tejada, Guillermo
author_sort Sánchez-Gómez, Susana
collection PubMed
description BACKGROUND: Infections by Pseudomonas aeruginosa constitute a serious health threat because this pathogen –particularly when it forms biofilms – can acquire resistance to the majority of conventional antibiotics. This study evaluated the antimicrobial activity of synthetic peptides based on LF11, an 11-mer peptide derived from human lactoferricin against P. aeruginosa planktonic and biofilm-forming cells. We included in this analysis selected N-acylated derivatives of the peptides to analyze the effect of acylation in antimicrobial activity. To assess the efficacy of compounds against planktonic bacteria, microdilution assays to determine the minimal inhibitory concentration (MIC), minimum bactericidal concentration (MBC) and time-kill studies were conducted. The anti-biofilm activity of the agents was assessed on biofilms grown under static (on microplates) and dynamic (in a CDC-reactor) flow regimes. RESULTS: The antimicrobial activity of lipopeptides differed from that of non-acylated peptides in their killing mechanisms on planktonic and biofilm-forming cells. Thus, acylation enhanced the bactericidal activity of the parental peptides and resulted in lipopeptides that were uniformly bactericidal at their MIC. In contrast, acylation of the most potent anti-biofilm peptides resulted in compounds with lower anti-biofilm activity. Both peptides and lipopeptides displayed very rapid killing kinetics and all of them required less than 21 min to reduce 1,000 times the viability of planktonic cells when tested at 2 times their MBC. The peptides, LF11-215 (FWRIRIRR) and LF11-227 (FWRRFWRR), displayed the most potent anti-biofilm activity causing a 10,000 fold reduction in cell viability after 1 h of treatment at 10 times their MIC. At that concentration, these two compounds exhibited low citotoxicity on human cells. In addition to its bactericidal activity, LF11-227 removed more that 50 % of the biofilm mass in independent assays. Peptide LF11-215 and two of the shortest and least hydrophobic lipopeptides, DI-MB-LF11-322 (2,2-dimethylbutanoyl-PFWRIRIRR) and DI-MB-LF11-215, penetrated deep into the biofilm structure and homogenously killed biofilm-forming bacteria. CONCLUSION: We identified peptides derived from human lactoferricin with potent antimicrobial activity against P. aeruginosa growing either in planktonic or in biofilm mode. Although further structure-activity relationship analyses are necessary to optimize the anti-biofilm activity of these compounds, the results indicate that lactoferricin derived peptides are promising anti-biofilm agents.
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spelling pubmed-44918692015-07-07 Antimicrobial activity of synthetic cationic peptides and lipopeptides derived from human lactoferricin against Pseudomonas aeruginosa planktonic cultures and biofilms Sánchez-Gómez, Susana Ferrer-Espada, Raquel Stewart, Philip S. Pitts, Betsey Lohner, Karl Martínez de Tejada, Guillermo BMC Microbiol Research Article BACKGROUND: Infections by Pseudomonas aeruginosa constitute a serious health threat because this pathogen –particularly when it forms biofilms – can acquire resistance to the majority of conventional antibiotics. This study evaluated the antimicrobial activity of synthetic peptides based on LF11, an 11-mer peptide derived from human lactoferricin against P. aeruginosa planktonic and biofilm-forming cells. We included in this analysis selected N-acylated derivatives of the peptides to analyze the effect of acylation in antimicrobial activity. To assess the efficacy of compounds against planktonic bacteria, microdilution assays to determine the minimal inhibitory concentration (MIC), minimum bactericidal concentration (MBC) and time-kill studies were conducted. The anti-biofilm activity of the agents was assessed on biofilms grown under static (on microplates) and dynamic (in a CDC-reactor) flow regimes. RESULTS: The antimicrobial activity of lipopeptides differed from that of non-acylated peptides in their killing mechanisms on planktonic and biofilm-forming cells. Thus, acylation enhanced the bactericidal activity of the parental peptides and resulted in lipopeptides that were uniformly bactericidal at their MIC. In contrast, acylation of the most potent anti-biofilm peptides resulted in compounds with lower anti-biofilm activity. Both peptides and lipopeptides displayed very rapid killing kinetics and all of them required less than 21 min to reduce 1,000 times the viability of planktonic cells when tested at 2 times their MBC. The peptides, LF11-215 (FWRIRIRR) and LF11-227 (FWRRFWRR), displayed the most potent anti-biofilm activity causing a 10,000 fold reduction in cell viability after 1 h of treatment at 10 times their MIC. At that concentration, these two compounds exhibited low citotoxicity on human cells. In addition to its bactericidal activity, LF11-227 removed more that 50 % of the biofilm mass in independent assays. Peptide LF11-215 and two of the shortest and least hydrophobic lipopeptides, DI-MB-LF11-322 (2,2-dimethylbutanoyl-PFWRIRIRR) and DI-MB-LF11-215, penetrated deep into the biofilm structure and homogenously killed biofilm-forming bacteria. CONCLUSION: We identified peptides derived from human lactoferricin with potent antimicrobial activity against P. aeruginosa growing either in planktonic or in biofilm mode. Although further structure-activity relationship analyses are necessary to optimize the anti-biofilm activity of these compounds, the results indicate that lactoferricin derived peptides are promising anti-biofilm agents. BioMed Central 2015-07-07 /pmc/articles/PMC4491869/ /pubmed/26149536 http://dx.doi.org/10.1186/s12866-015-0473-x Text en © Sánchez-Gómez et al. 2015 This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.
spellingShingle Research Article
Sánchez-Gómez, Susana
Ferrer-Espada, Raquel
Stewart, Philip S.
Pitts, Betsey
Lohner, Karl
Martínez de Tejada, Guillermo
Antimicrobial activity of synthetic cationic peptides and lipopeptides derived from human lactoferricin against Pseudomonas aeruginosa planktonic cultures and biofilms
title Antimicrobial activity of synthetic cationic peptides and lipopeptides derived from human lactoferricin against Pseudomonas aeruginosa planktonic cultures and biofilms
title_full Antimicrobial activity of synthetic cationic peptides and lipopeptides derived from human lactoferricin against Pseudomonas aeruginosa planktonic cultures and biofilms
title_fullStr Antimicrobial activity of synthetic cationic peptides and lipopeptides derived from human lactoferricin against Pseudomonas aeruginosa planktonic cultures and biofilms
title_full_unstemmed Antimicrobial activity of synthetic cationic peptides and lipopeptides derived from human lactoferricin against Pseudomonas aeruginosa planktonic cultures and biofilms
title_short Antimicrobial activity of synthetic cationic peptides and lipopeptides derived from human lactoferricin against Pseudomonas aeruginosa planktonic cultures and biofilms
title_sort antimicrobial activity of synthetic cationic peptides and lipopeptides derived from human lactoferricin against pseudomonas aeruginosa planktonic cultures and biofilms
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4491869/
https://www.ncbi.nlm.nih.gov/pubmed/26149536
http://dx.doi.org/10.1186/s12866-015-0473-x
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