Figure 5.

LxA₄ treatment can aid the efficacy of the antibiotic ciprofloxacin in reducing biofilm formation. Cultures were treated in a 96-well plate overnight with multiple concentrations of ciprofloxacin and LxA₄. The cultures and apical biofilm were washed away, and the remaining apical biofilm rings were stained with 0.1% crystal violet. Absorbance was measured at 600 nm. Some cultures were recovered from the 96-well plate, diluted and spread on tryptic soy agar plates to incubate overnight at 37°C. Colonies were counted the next day. (a) LxA₄ does not have an effect when combined with ciprofloxacin on non-adherent cell growth, determined by colony forming units (CFUs). (b) When combined with LxA₄, biofilm formation is significantly reduced in ciprofloxacin treatments at and above bactericidal doses (0.5 μg/mL). CFU data are mean ± s.e.m. of percent change from control adjusted to zero. Biofilm data are mean ± s.e.m. percent of control. ** = p < 0.01; CFUs n = 4 independent experiments; biofilm n = 6 (1 nM) and n = 3 (10 nM) independent experiments.