Staphylococcal cell death affects biofilm development and pathogenesis.

<p>(<b>A</b>) Representative CLSM micrographs of 1-day old biofilms of <i>S. aureus</i> UAMS-1 and isogenic mutants stained with SYTO9 (1.3 µM) and TOTO-3 (2 µM) to differentiate between live and dead cells. The images display top-down florescence projections of biofilms grown on glass slides (scale bar: 50 µm). Biofilm biomass (<b>B</b>), average thickness (<b>C</b>) and roughness coefficients (<b>D</b>) were calculated using the COMSTAT image analysis software, (statistical significance was assessed using one way ANOVA followed by Newman Kewl's multiple post-comparison test, n = 23; ** <i>P</i><0.005, *** <i>P</i><0.0005). (<b>E</b>) Experimental endocarditis was induced in rabbits by placement of a catheter into the left ventricle (see <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1004205#s4" target="_blank">materials and methods</a>). Bacteria (10⁵ cfu/ml) were inoculated 24 h after catheterization via the marginal ear vein. Animals were euthanized 48 h post infection, organs harvested and bacterial burdens determined by plating on tryptic soy agar plates (*, <i>P</i><0.05, one way ANOVA with Dunnets multiple comparison test, n = 5/strain).