Identification and Analysis of Staphylococcus aureus Components Expressed by a Model System of Growth in Serum

A model system mimicking Staphylococcus aureus bacteremia was developed by growth in serum under microaerobic conditions. Eight genes induced by growth in serum were identified, including an antimicrobial peptide biosynthesis locus, amino acid biosynthetic loci, and genes encoding putative surface proteins. Nine independent insertions were found in the major lysine biosynthesis operon, which encodes eight genes, is repressed by lysine in vitro, and is expressed in vivo.