A Thermostable Salmonella Phage Endolysin, Lys68, with Broad Bactericidal Properties against Gram-Negative Pathogens in Presence of Weak Acids

Resistance rates are increasing among several problematic Gram-negative pathogens, a fact that has encouraged the development of new antimicrobial agents. This paper characterizes a Salmonella phage endolysin (Lys68) and demonstrates its potential antimicrobial effectiveness when combined with organ...

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Vydané v:	PloS one Ročník 9; číslo 10; s. e108376
Hlavní autori:	Oliveira, Hugo, Thiagarajan, Viruthachalam, Walmagh, Maarten, Sillankorva, Sanna, Lavigne, Rob, Neves-Petersen, Maria Teresa, Kluskens, Leon D., Azeredo, Joana
Médium:	Journal Article
Jazyk:	English
Vydavateľské údaje:	United States Public Library of Science 07.10.2014 Public Library of Science (PLoS)
Predmet:	Acid resistance Acidity Analysis Anti-Bacterial Agents - chemistry Anti-Bacterial Agents - pharmacology Antimicrobial agents Bacteria Bioengineering Biofilms Biology and Life Sciences Cell Membrane Permeability Circular dichroism Citric acid Citric Acid - pharmacology Conformation Deoxyribonucleic acid Destabilization Dichroism DNA E coli Edetic acid Endopeptidases - chemistry Endopeptidases - genetics Endopeptidases - pharmacology Engineering Enzyme Stability Enzymes Escherichia coli Ethylenediaminetetraacetic acids Food industry Gram-negative bacteria Gram-Negative Bacteria - drug effects Hydrogen-Ion Concentration Hydrolysis Laboratories Malates - pharmacology Malic acid Organic acids Pathogenic microorganisms Pathogens pH effects Phages Protein denaturation Proteins Pseudomonas Salmonella Salmonella Phages - genetics Salmonella Phages - metabolism Thermal denaturation Thermal stability Thermodynamics United Kingdom > UK Belgium United States > US Portugal
ISSN:	1932-6203, 1932-6203
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Shrnutí:	Resistance rates are increasing among several problematic Gram-negative pathogens, a fact that has encouraged the development of new antimicrobial agents. This paper characterizes a Salmonella phage endolysin (Lys68) and demonstrates its potential antimicrobial effectiveness when combined with organic acids towards Gram-negative pathogens. Biochemical characterization reveals that Lys68 is more active at pH 7.0, maintaining 76.7% of its activity when stored at 4°C for two months. Thermostability tests showed that Lys68 is only completely inactivated upon exposure to 100°C for 30 min, and circular dichroism analysis demonstrated the ability to refold into its original conformation upon thermal denaturation. It was shown that Lys68 is able to lyse a wide panel of Gram-negative bacteria (13 different species) in combination with the outer membrane permeabilizers EDTA, citric and malic acid. While the EDTA/Lys68 combination only inactivated Pseudomonas strains, the use of citric or malic acid broadened Lys68 antibacterial effect to other Gram-negative pathogens (lytic activity against 9 and 11 species, respectively). Particularly against Salmonella Typhimurium LT2, the combinatory effect of malic or citric acid with Lys68 led to approximately 3 to 5 log reductions in bacterial load/CFUs after 2 hours, respectively, and was also able to reduce stationary-phase cells and bacterial biofilms by approximately 1 log. The broad killing capacity of malic/citric acid-Lys68 is explained by the destabilization and major disruptions of the cell outer membrane integrity due to the acidity caused by the organic acids and a relatively high muralytic activity of Lys68 at low pH. Lys68 demonstrates good (thermo)stability properties that combined with different outer membrane permeabilizers, could become useful to combat Gram-negative pathogens in agricultural, food and medical industry.
Bibliografia:	ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 14 content type line 23 Competing Interests: The authors have declared that no competing interests exist. Conceived and designed the experiments: SS RL MNP LK JA. Performed the experiments: HO VT MW. Analyzed the data: SS RL MNP LK JA. Contributed reagents/materials/analysis tools: RL MNP LK JA. Wrote the paper: HO VT.
ISSN:	1932-6203 1932-6203
DOI:	10.1371/journal.pone.0108376