BioProject

Streptococcus suis is a major pig pathogen as well as an emerging zoonotic pathogen. More...

Streptococcus suis is a major pig pathogen as well as an emerging zoonotic pathogen. Previous work has demonstrated that the S. suis extracellular amylopullulanase enzyme (ApuA) that degrades {alpha}-glucans also functions as an adhesin for porcine epithelial cells. To identify the mechanisms linking carbohydrate metabolism and virulence, we first compared the transcriptome of S. suis in minimal medium supplemented with glucose to minimal medium containing a complex carbohydrate pullulan as a carbon source. The relative expression of eighteen virulence genes including suilysin and apuA was increased during growth in presence of pullulan, compared to growth in glucose. Increased virulence potential of S. suis grown in pullulan was demonstrated using hemolytic assays and increased adhesion and invasion of porcine epithelial cells in vitro. A metabolic map of S. suis was generated and combined with transcriptome data to visualize the metabolic adaption of S. suis during adhesion and invasion of the porcine epithelial cells representing an in vitro model of infection. The role of carbon catabolite control in virulence gene regulation was investigated and the molecular mechanism of transcriptional regulation was elucidated for apuA. We demonstrate that relief of CcpA repression is a crucial transcriptional control mechanism linking carbohydrate mechanism and virulence. The model for the transcriptional regulation of two important virulence factors apuA and suilysin was verified by qPCR analysis of gene expression in S. suis recovered from the organs and blood of infected pigs. Overall design: Four-condition experiment (bacteria grown in THB or in CM supplemented with three different carbon sources), at two different timepoints (early exponential or late exponential growth phase). One replicate per array. Less...