Comparative secretome analysis of Staphylococcus aureus strains with different within-herd intramammary infection prevalence

This investigation reports a differential proteomic analysis of the secretome of six S. aureus strains belonging to two genotypes with opposite within-herd prevalence, GTB (high) and GTS (low), corresponding to sequence types (ST) 8 and 398, respectively. Total proteins released in the growth medium were subjected to high-resolution tandem mass spectrometry and differential analysis with Proteome Discoverer by label-free approach. Here, we reported both the characterization of secretome proteins and a panel of differential proteins specific of S. Aureus depending on high or low within-herd prevalence. GTB/ST8 (High) released more immunoglobulin-binding proteins, complement and antimicrobial peptide inhibitors, enterotoxins, and metabolic enzymes, while GTS/ST398 (Low) released more leukocidins, hemolysins, lipases, and peptidases. Furthermore, GTB/ST8 (High) released the von Willebrand factor protein, staphylokinase, and clumping factor B, while GTS/ST398 (Low) released the staphylococcal coagulase and clumping factor A. In conclusion, our results provide an in-depth characterization of secretome proteins of the three S. aureus GTB/ST8 and three GTS/ST398 strains with high and low within-herd prevalence. We describe the role of extracellular proteins in S. Aureus pathogenesis.