Figure 1

Biofilm assays. (A) Biofilm assays in 96 well microtitre plates were carried out as described in the text. Briefly, cells that were grown in BHI alone (- bile) or BHI containing 0.3% oxgall (+ bile) were washed and inoculated at equal cell numbers into fresh BHI broth and 200 μl was added to individual wells of a 96 well plate. After 24 hrs incubation at 37°C biofilms were stained with crystal violet and de-stained using ethanol and the optical density at 595 nm of the alcoholic crystal violet solutions was determined. Data is presented as averages +/- standard deviations for three biological repeats in one experiment. This result is representative of three independent experiments. (B) Representative images obtained from microscopic observations of biofilm on Petri dishes. Bacteria stained with crystal violet were observed under a 40× objective.