Concentration-response activity of increasing concentrations of moxifloxacin (0.125–32 mg L^{−1}) combined with pAcDED polymer (32 mg L^{−1}) against S. aureus biofilms (Clinical and reference strains). 24-h biofilms were incubated with increasing concentrations of moxifloxacin alone or in combination with pAcDED polymer for 48 h. The ordinate shows the change in resorufin fluorescence (bacterial viability) in percentage of the control value (no treatment). Black line, moxifloxacin alone; blue line, combinations; red point on dotted line, effect of pAcDED alone (32 mg L^{−1}).The squared concentration corresponds to moxifloxacin human C_max reached in the serum of patient receiving conventional dosages. All values are means ± standard deviations (SD) of four wells.