• DOI:10.1111/j.1365-2958.2005.04583.x
• Corpus ID: 14748436

Mutational analysis of the group A streptococcal operon encoding streptolysin S and its virulence role in invasive infection

@article{Datta2005MutationalAO,
  title={Mutational analysis of the group A streptococcal operon encoding streptolysin S and its virulence role in invasive infection},
  author={Vivekananda Datta and Sandra M Myskowski and Laura A Kwinn and Daniel N Chiem and Nissi Varki and Rita Kansal and Malak Kotb and Victor Nizet},
  journal={Molecular Microbiology},
  year={2005},
  volume={56}
}

• V. Datta, Sandra M Myskowski, +5 authors V. Nizet
• Published 1 May 2005
• Biology
• Molecular Microbiology

The pathogen group A Streptococcus (GAS) produces a wide spectrum of infections including necrotizing fasciitis (NF). Streptolysin S (SLS) produces the hallmark β‐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.