FIGURE 4.

Lactoferrin eradicates pneumococcal colonization on human HEp-2 cells. Streptococcus pneumoniae strain D39 (7.5 × 10⁴ CFU/ml) was inoculated in cultures of human HEp-2 cells and incubated for 4 h (A,B) or 8 h (C) at 37°C with 5% CO₂. Planktonic cells were removed and biofilms were washed and treated with bovine Lactoferrin (bLF) for 6 h (A,C) or 12 h (B). Treated pneumococci were harvested, diluted, and platted on blood agar plates to obtain viable cells. 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.