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Updated: Mar 14, 2026
Intracranial Subarachnoidal Route of Infection for Investigating Roles of Streptococcus suis Biofilms in Meningitis in a Mouse Infection Model
Published on: July 1, 2018
Streptococcus suis Serotype 2 Capsule In Vivo
Abstract:
Many Streptococcus suis isolates from porcine endocarditis in slaughterhouses have lost their capsule and are considered avirulent. However, we retrieved capsule- and virulence-recovered S. suis after in vivo passages of a nonencapsulated strain in mice, suggesting that nonencapsulated S. suis are still potentially hazardous for persons in the swine industry.
Insights
Nonencapsulated Streptococcus suis strains, often deemed harmless, can regain virulence after mouse passages. This highlights potential risks for swine industry workers exposed to these bacteria.
Area of Science:
- Veterinary Microbiology
- Bacterial Pathogenesis
- Zoonotic Diseases
Background:
- Streptococcus suis is a significant swine pathogen causing endocarditis.
- Many isolates from diseased pigs lack capsules and are considered avirulent.
- Capsular expression is crucial for S. suis virulence.
Purpose of the Study:
- To investigate the potential for nonencapsulated Streptococcus suis to regain virulence.
- To assess the risk posed by avirulent S. suis strains in the swine industry.
Main Methods:
- Passaging a nonencapsulated S. suis strain through mice.
- Monitoring for capsule re-expression and virulence markers in recovered isolates.
Main Results:
- Encapsulated and virulent S. suis strains were recovered after in vivo mouse passages.
- Nonencapsulated strains demonstrated the capacity to revert to a virulent phenotype.
Conclusions:
- Avirulent, nonencapsulated Streptococcus suis strains may pose an underestimated risk.
- Further research is needed to understand the mechanisms of virulence recovery in S. suis.
- Enhanced surveillance and control measures are warranted for S. suis in swine populations.
