Fig. 3.

Post long-term exposure changes in the MBIC A, B and MBEC C, D of NAg, Ag⁺ and gentamicin (GM) on the respective mid-point passaged A, C and end-point passaged B, D strains (24 h exposure, 37 °C). Biofilm biomass is expressed as % relative to the cell-only control (no antimicrobial agent, 0 µg/mL). Error bars represent SEM (standard error of the mean) of three biological replicates (experiments with independent bacterial inocula from three isolates and different antimicrobial preparations, each with three technical replicates). *Indicates statistically significant biofilm growth inhibition A, B and eradication of established biomass C, D with p > 0.05 (not significant, ns), p < 0.05 (*), p < 0.01 (**), p < 0.001 (***) and p < 0.0001 (****), relative to the cell-only control. The MBIC and MBEC studies of the second biological replicate of the passaging experiment are presented in Additional file 1: Figure S2