FIGURE 2.

Lactoferrin but not its derived peptides destroy preformed Streptococcus pneumoniae biofilms. 7.5 × 10⁴ CFU/ml S. pneumoniae strain D39 were inoculated in a 24-well plate containing THY and then plates were incubated for 4 h (A,B) or 8 h (C) at 37°C with 5% CO₂. After that, planktonic cells were removed, biofilms were washed and then treated with 40 μM bLF, 10 μM LFcin17-30, 10 μM LFampinn265-284, and 10 μM LFchimera for 6 h (A,C) or 12 h (B). Treated biofilms were harvested, diluted, and platted on blood agar plates to obtain viable counts. Experiments were repeated at least three times. Standard deviation of the mean is shown. Asterisks indicate statistical significance calculated using the ANOVA test (p < 0.05). Viable counts of pneumococci in the untreated control were adjusted to 100% and viability on those treated was calculated.