Virulence of Streptococcus canis from canine streptococcal toxic shock syndrome and necrotizing fasciitis

Vet Microbiol. 1999 Oct;70(1-2):95-110. doi: 10.1016/s0378-1135(99)00128-5.


The recent recognition of streptococcal toxic shock syndrome (STSS) and necrotizing fasciitis (NF) in dogs caused by Streptococcus canis highlights our lack of knowledge regarding the mechanisms of virulence of this organism. Fifteen isolates of S. canis from cases of canine STSS and/or NF were examined for the presence of 10 Streptococcus pyogenes-associated virulence genes by Southern hybridizations using gene probes generated by PCR. The isolates lacked DNA with homology to eight of the 10 gene probes (speA, speB, speC, mf, ssa, scp, hasA, ska) under low stringency conditions. Thirteen and 15 of 15 isolates hybridized with streptolysin O and M protein gene probes, respectively. Twelve of 15 S. canis isolates were resistant to phagocytosis in canine blood. Electron microscopy revealed the presence of proteinaceous cell surface fibrillae. These results suggest that S. canis possesses M proteins and encodes streptolysin O, but lacks some of the other recognized virulence genes with significant homology to those in S. pyogenes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Antigens, Bacterial / analysis
  • Bacterial Outer Membrane Proteins*
  • Bacterial Proteins / analysis
  • Base Sequence
  • Carrier Proteins / analysis
  • Dog Diseases / microbiology*
  • Dogs
  • Exotoxins / analysis
  • Fasciitis, Necrotizing / microbiology
  • Fasciitis, Necrotizing / veterinary*
  • Membrane Proteins*
  • Molecular Sequence Data
  • Phagocytosis
  • Shock, Septic / microbiology
  • Shock, Septic / veterinary*
  • Streptococcus / isolation & purification
  • Streptococcus / pathogenicity*
  • Streptokinase / analysis
  • Streptolysins / analysis
  • Superantigens / analysis


  • Antigens, Bacterial
  • Bacterial Outer Membrane Proteins
  • Bacterial Proteins
  • Carrier Proteins
  • Exotoxins
  • Membrane Proteins
  • SpeA protein, Streptococcus pyogenes
  • Streptolysins
  • Superantigens
  • erythrogenic toxin
  • streptococcal M protein
  • streptococcal superantigen SSA
  • streptolysin O
  • Streptokinase