Determination of the minimum biofilm eradication concentration of cysteamine against established P. aeruginosa DSMZ1299 (A) and P. aeruginosa ATCC27853 (B) biofilms. Cys – cysteamine. The optical density (492 nm) of crystal violet released from adherent cells within 24 h biofilms was used as an index of biofilm formation. A biofilm-positive phenotype was defined as OD ≥ 0.2. To compensate for background absorbance, OD readings of the sterile medium with both the fixative and dye were subtracted from all the experimental values. Experiments were performed in triplicate and results are presented as means. Error bars represent the standard error of the mean.