Streptococcus suis vaccines: candidate antigens and progress

Abstract

Streptococcus suis is a major swine pathogen and an emerging zoonotic agent of human meningitis and streptococcal toxic shock-like syndrome. S. suis is a well-encapsulated pathogen and multiple serotypes have been described based on the capsular polysaccharide antigenic diversity. In addition, high genotypic, phenotypic and geographic variability exits among strains within the same serotype. Besides, S. suis uses an arsenal of virulence factors to evade the host immune system. Together, these characteristics have challenged the development of efficacious vaccines to fight this important pathogen. In this careful and comprehensive review, clinical field information and experimental data have been compiled and compared for the first time to give a precise overview of the current status of vaccine development against S. suis. The candidate antigens and vaccine formulations under research are examined and the feasibility of reaching the goal of a “universal” cross-protective S. suis vaccine discussed.

Keywords:

• invasive Streptococcus suis disease
• zoonosis
• swine production
• serotypes and sequence types
• bacterins
• live-attenuated vaccines
• sub-unit vaccines
• cross-protection

Acknowledgements

The author would like to thank Marcelo Gottschalk (University of Montreal) for critical discussions during the writing of this manuscript.