Fig 1. Workflow applied for the identification of pneumococcal-specific proteins from mouse CSF isolates.

In a first step, S. pneumoniae D39 specific tandem-MS spectra from different conditions were measured and stored in a database (spectral library; SpectraST). Subsequently, proteins from S. pneumoniae in vivo experiments were measured after dual filter extraction and digestion steps and compared and aligned to spectra deposited in the database. A subset of proteins exclusively identified in vivo in the CSF was further considered for phenotypical characterization and for demonstrating its impact on pneumococcal meningitis.