FIG 2.

H₂S influenced biofilm formation of S. mitis and S. oralis. (A and B) Viability of planktonic titers of S. mitis (A) and S. oralis (B) in the presence and absence of NaHS from a starting inoculum of 1 × 10⁶ CFU/ml after 24 h. (C to F) S. mitis and S. oralis biofilms were formed on a saliva-coated polystyrene well plate in the presence and absence of NaHS from a starting inoculum of 1 × 10⁶ CFU/ml for 24 h. The thickness of S. mitis (C) and S. oralis (D) biofilms was determined by crystal violet assay. The viability of S. mitis (E) and S. oralis (F) bacteria in biofilm was determined by serial dilution and plating on a BHI agar plate. The experiments were carried out 3 times, each time in triplicate. Data shown are the mean results obtained from 3 independent experiments. ***, P < 0.001.