TY - JOUR

T1 - Comparative Evaluation of the Antimicrobial Activity of Different Antimicrobial Peptides against a Range of Pathogenic Bacteria

AU - Ebbensgaard, Anna

AU - Mordhorst, Hanne

AU - Overgaard, Michael Toft

AU - Nielsen, Claus Gyrup

AU - Aarestrup, Frank Møller

AU - Hansen, Egon Bech

PY - 2015

Y1 - 2015

N2 - ANALYSIS OF A SELECTED SET OF ANTIMICROBIAL PEPTIDES: The rapid emergence of resistance to classical antibiotics has increased the interest in novel antimicrobial compounds. Antimicrobial peptides (AMPs) represent an attractive alternative to classical antibiotics and a number of different studies have reported antimicrobial activity data of various AMPs, but there is only limited comparative data available. The mode of action for many AMPs is largely unknown even though several models have suggested that the lipopolysaccharides (LPS) play a crucial role in the attraction and attachment of the AMP to the bacterial membrane in Gram-negative bacteria. We compared the potency of Cap18, Cap11, Cap11-1-18m2, Cecropin P1, Cecropin B, Bac2A, Bac2A-NH2, Sub5-NH2, Indolicidin, Melittin, Myxinidin, Myxinidin-NH2, Pyrrhocoricin, Apidaecin and Metalnikowin I towards Staphylococcus aureus, Enterococcus faecalis, Pseudomonas aeruginosa, Escherichia coli, Aeromonas salmonicida, Listeria monocytogenes, Campylobacter jejuni, Flavobacterium psychrophilum, Salmonella typhimurium and Yersinia ruckeri by minimal inhibitory concentration (MIC) determinations. Additional characteristics such as cytotoxicity, thermo and protease stability were measured and compared among the different peptides. Further, the antimicrobial activity of a selection of cationic AMPs was investigated in various E. coli LPS mutants.CAP18 SHOWS A HIGH BROAD SPECTRUM ANTIMICROBIAL ACTIVITY: Of all the tested AMPs, Cap18 showed the most efficient antimicrobial activity, in particular against Gram-negative bacteria. In addition, Cap18 is highly thermostable and showed no cytotoxic effect in a hemolytic assay, measured at the concentration used. However, Cap18 is, as most of the tested AMPs, sensitive to proteolytic digestion in vitro. Thus, Cap18 is an excellent candidate for further development into practical use; however, modifications that should reduce the protease sensitivity would be needed. In addition, our findings from analyzing LPS mutant strains suggest that the core oligosaccharide of the LPS molecule is not essential for the antimicrobial activity of cationic AMPs, but in fact has a protective role against AMPs.

AB - ANALYSIS OF A SELECTED SET OF ANTIMICROBIAL PEPTIDES: The rapid emergence of resistance to classical antibiotics has increased the interest in novel antimicrobial compounds. Antimicrobial peptides (AMPs) represent an attractive alternative to classical antibiotics and a number of different studies have reported antimicrobial activity data of various AMPs, but there is only limited comparative data available. The mode of action for many AMPs is largely unknown even though several models have suggested that the lipopolysaccharides (LPS) play a crucial role in the attraction and attachment of the AMP to the bacterial membrane in Gram-negative bacteria. We compared the potency of Cap18, Cap11, Cap11-1-18m2, Cecropin P1, Cecropin B, Bac2A, Bac2A-NH2, Sub5-NH2, Indolicidin, Melittin, Myxinidin, Myxinidin-NH2, Pyrrhocoricin, Apidaecin and Metalnikowin I towards Staphylococcus aureus, Enterococcus faecalis, Pseudomonas aeruginosa, Escherichia coli, Aeromonas salmonicida, Listeria monocytogenes, Campylobacter jejuni, Flavobacterium psychrophilum, Salmonella typhimurium and Yersinia ruckeri by minimal inhibitory concentration (MIC) determinations. Additional characteristics such as cytotoxicity, thermo and protease stability were measured and compared among the different peptides. Further, the antimicrobial activity of a selection of cationic AMPs was investigated in various E. coli LPS mutants.CAP18 SHOWS A HIGH BROAD SPECTRUM ANTIMICROBIAL ACTIVITY: Of all the tested AMPs, Cap18 showed the most efficient antimicrobial activity, in particular against Gram-negative bacteria. In addition, Cap18 is highly thermostable and showed no cytotoxic effect in a hemolytic assay, measured at the concentration used. However, Cap18 is, as most of the tested AMPs, sensitive to proteolytic digestion in vitro. Thus, Cap18 is an excellent candidate for further development into practical use; however, modifications that should reduce the protease sensitivity would be needed. In addition, our findings from analyzing LPS mutant strains suggest that the core oligosaccharide of the LPS molecule is not essential for the antimicrobial activity of cationic AMPs, but in fact has a protective role against AMPs.

KW - Amino Acid Sequence

KW - Animals

KW - Anti-Bacterial Agents/chemistry

KW - Antimicrobial Cationic Peptides/chemistry

KW - Drug Resistance, Multiple, Bacterial/genetics

KW - Erythrocytes/cytology

KW - Gram-Negative Bacteria/drug effects

KW - Gram-Positive Bacteria/drug effects

KW - Hemolysis/drug effects

KW - Horses

KW - Lipopolysaccharides/chemistry

KW - Microbial Sensitivity Tests

KW - Molecular Sequence Data

KW - Mutation

KW - Peptide Hydrolases/chemistry

KW - Protein Stability

KW - Proteolysis

KW - Structure-Activity Relationship

KW - Temperature

U2 - 10.1371/journal.pone.0144611

DO - 10.1371/journal.pone.0144611

M3 - Journal article

C2 - 26656394

VL - 10

SP - e0144611

JO - PLoS ONE

JF - PLoS ONE

SN - 1932-6203

IS - 12

ER -