Identification of genes transcribed by Streptococcus equi ssp. zooepidemicus in infected porcine lung.

Streptococcus equi ssp. zooepidemicus (SEZ) is a Gram-positive bacterium responsible for respiratory tract infection, septicemia, meningitis, endocarditis and arthritis in swine and humans. However, the expression and regulation of SEZ genes during an infection in vivo are poorly understood. In this study, we focused on the identification of SEZ genes preferentially expressed in vivo during infection in pigs. This study identified 45 SEZ genes that were upregulated in infected porcine lung tissues using the selective capture of transcribed sequences (SCOTS) technique and comparative dot-blot analysis, followed by quantitative RT-PCR validation. The identified genes were characterized into 6 functional categories: metabolism, cell wall-associated, stress response, transporters, regulators and unknown functions. Our study successfully identified multiple genes, which can deepen our understanding about SEZ pathogenesis and infer probable virulence factors. It will promote the development of novel vaccines and therapies about this pathogen for further study.