FIGURE 1.

Skin colonization model and experimental time course. (A) To analyze the adaptation of S. aureus to the epidermis, skin explants were colonized with either exponentially or post-exponentially grown S. aureus USA300 and transcript analyzes were performed up to 18 h. For a broad screening of genes, skin samples were colonized with exponentially grown bacteria and transcript analyses were carried out at 9 different times indicated with an asterisk. Time points marked in blue are defined as early colonization and red marked times are defined as late colonization. (B) Skin explant viability by MTT assay. A reduction in color from yellow color to purple formazan has been observed in living skin biopsies for up to 8 days. (C) Relative gyrB mRNA expression over time. Exp, exponential phase; pxp, post-exponential phase.