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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
2005-4-11
pubmed:abstractText
The pathogen group A Streptococcus (GAS) produces a wide spectrum of infections including necrotizing fasciitis (NF). Streptolysin S (SLS) produces the hallmark beta-haemolytic phenotype produced by GAS. The nine-gene GAS locus (sagA-sagI) resembling a bacteriocin biosynthetic operon is necessary and sufficient for SLS production. Using precise, in-frame allelic exchange mutagenesis and single-gene complementation, we show sagA, sagB, sagC, sagD, sagE, sagF and sagG are each individually required for SLS production, and that sagE may further serve an immunity function. Limited site-directed mutagenesis of specific amino acids in the SagA prepropeptide supports the designation of SLS as a bacteriocin-like toxin. No significant pleotrophic effects of sagA deletion were observed on M protein, capsule or cysteine protease production. In a murine model of NF, the SLS-negative M1T1 GAS mutant was markedly diminished in its ability to produce necrotic skin ulcers and spread to the systemic circulation. The SLS toxin impaired phagocytic clearance and promoted epithelial cell cytotoxicity, the latter phenotype being enhanced by the effects of M protein and streptolysin O. We conclude that all genetic components of the sag operon are required for expression of functional SLS, an important virulence factor in the pathogenesis of invasive M1T1 GAS infection.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0950-382X
pubmed:author
pubmed:issnType
Print
pubmed:volume
56
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
681-95
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed-meshheading:15819624-Amino Acid Sequence, pubmed-meshheading:15819624-Animals, pubmed-meshheading:15819624-Antigens, Bacterial, pubmed-meshheading:15819624-Bacterial Outer Membrane Proteins, pubmed-meshheading:15819624-Bacterial Proteins, pubmed-meshheading:15819624-Carrier Proteins, pubmed-meshheading:15819624-Genetic Complementation Test, pubmed-meshheading:15819624-Humans, pubmed-meshheading:15819624-Male, pubmed-meshheading:15819624-Mice, pubmed-meshheading:15819624-Molecular Sequence Data, pubmed-meshheading:15819624-Mutagenesis, Site-Directed, pubmed-meshheading:15819624-Operon, pubmed-meshheading:15819624-Phagocytosis, pubmed-meshheading:15819624-Skin Diseases, Bacterial, pubmed-meshheading:15819624-Streptococcal Infections, pubmed-meshheading:15819624-Streptococcus, pubmed-meshheading:15819624-Streptolysins, pubmed-meshheading:15819624-Virulence
pubmed:year
2005
pubmed:articleTitle
Mutational analysis of the group A streptococcal operon encoding streptolysin S and its virulence role in invasive infection.
pubmed:affiliation
Department of Pediatrics, Division of Infectious Diseases, University of California, San Diego, La Jolla, CA, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't, Research Support, N.I.H., Extramural