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Updated: Jan 13, 2026
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Intracranial Subarachnoidal Route of Infection for Investigating Roles of Streptococcus suis Biofilms in Meningitis in a Mouse Infection Model
Published on: July 1, 2018
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A two-component system regulating suilysin production in ST1 serotype 2 Streptococcus suis.
Michelle Wiebe1, Angelo Antiguas1, Sashi Kant1
1Boehringer Ingelheim Animal Health USA, Inc., Ames, IA, USA.
Veterinary Microbiology
|January 10, 2026
Summary
The Ihk/Irr system controls suilysin production in Streptococcus suis, a key virulence factor. This discovery offers new insights into regulating this important zoonotic pathogen.
Area of Science:
- Microbiology
- Bacteriology
- Pathogen Research
Background:
- Streptococcus suis is a significant zoonotic pathogen impacting swine and human health.
- Suilysin, a cytotoxin produced by S. suis, is a crucial virulence factor for invasion and dissemination.
- Understanding the regulation of suilysin is vital for controlling S. suis infections.
Purpose of the Study:
- To investigate the role of the Ihk/Irr two-component system in regulating suilysin production in S. suis.
- To identify other virulence-associated genes controlled by the Ihk/Irr system.
Main Methods:
- Genetic manipulation of S. suis strains to delete ihk and irr genes.
- Quantitative analysis of suilysin transcript and protein levels.
- Assessment of bacterial cytotoxicity.
- Genome-wide transcriptomic analysis (RNA-Seq).
Main Results:
- Deletion of ihk and irr genes significantly reduced suilysin expression and bacterial cytotoxicity.
- The Ihk/Irr system regulates a wide range of genes beyond suilysin.
- Identified regulatory targets include transcriptional regulators, ABC transporters, Sao, and PepO.
Conclusions:
- The Ihk/Irr two-component system is a key regulator of suilysin and other virulence factors in S. suis.
- This finding provides a deeper understanding of S. suis virulence mechanisms.
- Highlights potential targets for therapeutic intervention against S. suis.
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