CLSM images of H. pylori strains TK1402 (A) and SS1 (B) biofilms in Brucella broth containing 7% FCS. Each image represents the layer in the Z-stack that has the maximum bacterial coverage. The 3-day biofilms of each strain were stained with BacLight LIVE/DEAD stain. Viable cells are colored green and nonviable cells are colored red. x-z and y-z reconstructions of each biofilm are shown on the right and upper sides of each x-y image. The scale bars equal 50 μm in both panels. (C) Biofilm thickness of each strain. Each biofilm was scanned with CLSM at five randomly selected positions and x-z color detection, corresponding to biofilm thickness, was determined throughout the height of the biofilm. Data are representative of three independent experiments. The results are expressed as the means ± standard deviations. SEM images of H. pylori strains TK1402 (D) and SS1 (E) biofilms in Brucella broth containing 7% FCS. The 3-day biofilm of each strain on cover glass was investigated using SEM. The OMV-like structures are indicated by white arrows (D). Scale bars (2 μm) are shown at the bottom of each electron micrograph. *significantly different relative levels of biofilm thickness (p < 0.05; strain TK1402 versus other strains).