Figure 7. Confocal laser scanning microscopy image of the viability of biofilm-grown S. pneumoniae R6 in the presence of CSA-13.

Pneumococcal strains (4.5×10⁴ CFU) were grown on glass-bottom dishes (WillCo-dish) in 2 ml of C medium for 12 h at 34°C. The pneumococcal biofilms were rinsed with C medium to remove non-adherent bacteria, and then incubated with CSA-13 at 5 µg/ml (b) or 25 µg/ml (c) for 90 min at 34°C. Panel a shows untreated control biofilm. Cells in the biofilms were stained with the BacLight bacterial viability kit to reveal living (green) and dead (red) bacteria.