Resistance to the antimicrobial polymyxin B and other antibiofilm molecules. (A) Assay of polymyxin B susceptibility of WT strain TG1-c and mutant strains partially resistant to G2cps biofilms. (B) Biofilm ratio of the WT in the presence of the other antibiofilm molecules produced by strains iai44, Ec094, iai73, and H19, surfactin, and Tween 80. (C to H) Comparison of biofilm ratios of the WT and mutants partially resistant to G2cps in the presence of antibiofilm supernatants of strains Ec094 (C), iai44 (D), iai73 (E), and H19 (F) and in the presence of surfactin (G) and Tween 80 (H). *, P ≤ 0.05; **, P ≤ 0.01; ***, P ≤ 0.005. P values were determined with respect to the WT biofilm ratio (black bars).