Capsular polysaccharide switching in Streptococcus suis modulates host cell interactions and virulence
Masatoshi Okura1, Jean-Philippe Auger2, Tomoyuki Shibahara3,4
1Division of Bacterial and Parasitic Diseases, National Institute of Animal Health, National Agriculture and Food Research Organization, Tsukuba, Ibaraki, Japan. mokura@affrc.go.jp.
Scientific Reports
|March 23, 2021
Summary
Streptococcus suis serotype switching significantly alters virulence and host interactions. Some capsular polysaccharide (CPS) serotypes increase hyper-virulence, while others reduce it, impacting disease potential.
Area of Science:
- Microbiology
- Bacterial Pathogenesis
- Immunology
Background:
- Streptococcus suis capsular polysaccharide (CPS) defines serotypes.
- Serotype switching in S. suis is proposed but its impact on virulence is unknown.
Purpose of the Study:
- To investigate the impact of experimentally induced S. suis serotype switching on virulence and host cell interactions.
- To assess how different CPS serotypes affect bacterial properties like adhesion, invasion, and immune evasion.
Main Methods:
- Generated S. suis serotype-switched mutants expressing CPS from serotypes 3, 4, 7, 8, 9, and 14.
- Evaluated mutant properties including epithelial cell adhesion/invasion, macrophage phagocytosis resistance, whole blood killing, and dendritic cell responses.
- Assessed virulence in mouse and porcine infection models.
Main Results:
- Serotype switching differentially modulated host cell interactions based on the CPS type.
- Mutants expressing serotype 8 CPS showed hyper-virulence; serotype 3 or 4 CPS mutants had reduced virulence.
- Switching to serotype 7, 9, or 14 CPS had minimal impact on virulence.
Conclusions:
- S. suis serotype switching can drastically alter bacterial virulence.
- CPS serotype is a key determinant of S. suis pathogenicity and host-pathogen interactions.
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