FIG. 4.

FnBPs confer invasiveness to noninvasive S. carnosus. Overexpression (+++) of adhesins in strain TM300 by multicopy plasmids was tested for invasion of 293 cells. (A) Total internalized bacteria were measured by lysostaphin (20 μg/ml) protection. Results are means and SEMs for five independent experiments (ClfA, n = 2) run in duplicate and are expressed as recovered CFU, normalized for the actual inoculum. Similar results were obtained when penicillin (2 μg/ml) was used instead of lysostaphin (data not shown). (B) Total internalized bacteria were measured by flow cytometry with fixed bacteria. Results are means and SEMs for three independent experiments (ClfA, n = 2) run in duplicate and are expressed as invasiveness relative to that of strain Cowan 1. AFU, arbitrary fluorescence units; WT, wild type.