Abstract
We generated by allelic replacement a DeltadltA mutant of a virulent Streptococcus suis serotype 2 field strain and evaluated the contribution of lipoteichoic acid (LTA) d-alanylation to the virulence traits of this swine pathogen and zoonotic agent. The absence of LTA D-alanylation resulted in increased susceptibility to the action of cationic antimicrobial peptides. In addition, and in contrast to the wild-type strain, the DeltadltA mutant was efficiently killed by porcine neutrophils and showed diminished adherence to and invasion of porcine brain microvascular endothelial cells. Finally, the DeltadltA mutant was attenuated in both the CD1 mouse and porcine models of infection, probably reflecting a decreased ability to escape immune clearance mechanisms and an impaired capacity to move across host barriers. The results of this study suggest that LTA D-alanylation is an important factor in S. suis virulence.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Alanine / metabolism*
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Animals
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Anti-Bacterial Agents / pharmacology
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Antimicrobial Cationic Peptides / pharmacology
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Bacterial Adhesion
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Bacterial Proteins / genetics
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Carbon-Oxygen Ligases
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Cell Line
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D-Alanine Transaminase / genetics
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Endothelial Cells / microbiology
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Female
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Gene Deletion
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Lipopolysaccharides / metabolism*
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Magnetic Resonance Spectroscopy
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Mice
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Microbial Viability
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Neutrophils / immunology
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Streptococcal Infections / microbiology
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Streptococcus suis / drug effects
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Streptococcus suis / genetics
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Streptococcus suis / immunology
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Streptococcus suis / pathogenicity*
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Survival Analysis
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Swine
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Teichoic Acids / metabolism*
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Virulence
Substances
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Anti-Bacterial Agents
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Antimicrobial Cationic Peptides
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Bacterial Proteins
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Lipopolysaccharides
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Teichoic Acids
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lipoteichoic acid
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D-Alanine Transaminase
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Carbon-Oxygen Ligases
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DltA protein, Bacillus subtilis
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Alanine