S. uberis proteins from sub-cellular fractions (both cell wall-attached and secreted) were separated with SDS-PAGE, trypsine digested and identified with MS/MS analysis. Extracellular proteins were clustered into functional group based on in silico analysis. Concerning the database search: Mascot 2.2.0 was used with the following parameters: significance threshold p<0.05, Mascot MS/MS ion search : database NCBI, allow up to 1 miss cleavage, fixed modification - carbamidomethyl(C), variable modification- oxidation, peptide tol. +/- 1.5 Da, MS/MS tol. +/- 0.5 Da, monoisotopic.