Date Full Report Received


Date Abstract Report Received



Primary Investigator:

Streptococcus suis is a key swine pathogen responsible for significant economic losses to the swine industry worldwide. S. suis is capable of causing a wide variety of clinical diseases in pigs including pneumonia, meningitis, septicemia, and endocarditis. Additionally, S. suis is a zoonotic pathogen causing severe infections in people due to penetrating injuries associated with occupational exposure or consumption of raw or undercooked pork products. Despite the significant impact on swine health and public health implications, the strategies and mechanisms used by S. suis to colonize and cause disease remain unknown. More importantly, vaccines and/or intervention strategies that do not rely on broad spectrum antibiotics currently do not exist to mitigate S. suis disease burden. The overall goal of this project was to use an unbiased and comprehensive approach to identify genomic and/ or transcriptional differences responsible for the spectrum of virulent capacities that occur among S. suis strains. Whole genome sequencing followed by comparative genomic analyses revealed several notable regions of difference, including regions encoding secreted and membrane-associated factors, which likely contributed to the spectrum of clinical disease observed. Transcriptome sequencing was performed on virulent and nonvirulent isolates following incubation in whole pig blood. Numerous laboratory assays were performed to test the capacity of these strains to adhere, survive, and/or persist within conditions that mimic various host microenvironments. Collectively, these results provide a foundation for understanding the genomic attributes responsible for the spectrum of virulent phenotypes that exist among S. suis isolates. This information is paramount to designing effective vaccines needed by the swine industry to mitigate S. suis disease and decrease public health concerns.

Contact Information:
Tracy L. Nicholson, Ph.D.
National Animal Disease Center, ARS, USDA
1920 Dayton Ave.
Ames, Iowa 50010
Telephone: +1 515 337 7349
E-mail: tracy.nicholson@ARS.USDA.GOV