Streptococcus suis serotype 2 binding to extracellular matrix proteins

Miriam Esgleas1, Sonia Lacouture, Marcelo Gottschalk

  • 1Groupe de Recherche sur les Maladies Infectieuses du Porc (GREMIP), Faculté de médecine vétérinaire, Université de Montréal, Qué., Canada.

FEMS Microbiology Letters
|February 25, 2005
PubMed

Insights

Streptococcus suis serotype 2 binds to extracellular matrix proteins like fibronectin and collagen, crucial for infections. Its capsule hinders this binding, suggesting protein adhesins are key targets.

Area of Science:

  • Microbiology
  • Pathogen Research
  • Bacterial Adherence

Background:

  • Streptococcus suis serotype 2 is a significant pathogen in swine and humans, causing severe diseases like septicemia and meningitis.
  • Understanding bacterial adherence mechanisms is critical for developing effective treatments and preventative strategies against S. suis infections.

Purpose of the Study:

  • To investigate the binding capabilities of Streptococcus suis serotype 2 to various extracellular matrix (ECM) proteins.
  • To explore the role of the bacterial capsule and surface molecules in ECM protein adherence.

Main Methods:

  • Enzyme-linked immunosorbent assay (ELISA) was employed to assess the binding of S. suis serotype 2 strains to different ECM proteins.
  • Adherence assays included cross-inhibition studies and pre-incubation experiments with fibronectin and collagens.
  • Heat treatment and proteolytic digestion were used to determine the nature of bacterial adhesins.

Main Results:

  • All tested S. suis serotype 2 strains demonstrated binding to plasma fibronectin and collagens (types I, III, V), with variable binding to fibrin, vitronectin, and laminin.
  • An unencapsulated mutant exhibited enhanced ECM protein binding compared to its encapsulated parent strain, indicating capsule interference.
  • Cross-inhibition studies suggested shared or nearby binding sites for fibronectin and collagens on bacterial surface molecules.

Conclusions:

  • Streptococcus suis serotype 2 possesses proteinaceous adhesins that mediate binding to key extracellular matrix proteins.
  • The bacterial polysaccharide capsule plays a role in modulating ECM adherence.
  • Fibronectin may act as a bridging molecule, facilitating bacterial interaction with other ECM components like collagen IV.

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