Identification of novel virulence factors of Streptococcus suis:
Streptococcus suis is a porcine pathogen with a zoonotic importance. It causes septicemia, meningitis, arthritis, and pneumonia mainly in weaning pigs. In humans, the clinical signs resemble those in pigs. A better knowledge on virulence factors and their role in infection is urgently needed to develop improved control strategies. To gain more insights into virulence mechanisms and immune responses during S. suis infection, we are applying two in vitro models, porcine PCLS and ALI-cultures, which closely resemble the in vivo conditions in the respiratory tract of pigs and, thus, help to reduce the number of animal experiments.
First results of our ongoing studies indicate that genes coding for inflammatory cytokines, chemokines, transcriptional regulators and inflammatory response genes are upregulated in response of porcine respiratory cells to S. suis. Furthermore, these models allowed us to identify bacterial genes, which are differentially expressed during infection. Such genes may well be involved in the infection process and, thus, will enable the identification of novel and/or previously uncharacterized virulence-associated factors of S. suis.