(A) Biofilm formation by eight H. pylori strains. The graph shows quantification of biofilms formed after 3-days (white bars) and 5-days (black bars) following culture in Brucella broth containing 7% FCS. (B) Eight H. pylori strains were grown in Brucella broth containing 7% FCS-, and OD600 absorbance was measured at 3-days (white bars) and 5-days (black bars). (C, and D) Time course experiments for the H. pylori strains TK1402 (C) and SS1 (D) biofilm formation and their growth. The biofilm mass of these strains are shown as black bars and the lines depict the OD600 absorbances of these strains. All of the results were expressed as the means ± standard deviations from at least three independent experiments. *significantly different (p < 0.05) relative level of biofilm formation (strain TK1402 versus other strains).