Figure 6.

LxA₄ in combination with imipenem significantly decreased non-adherent cell growth but not biofilm formation. Cultures were treated in a 96-well plate overnight with multiple concentrations of imipenem 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 a 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 (10 nM) in combination with imipenem (0.1 μg/mL) significantly decreased non-adherent cell growth. (b) LxA₄ does not significantly affect the efficacy of imipenem against biofilm formation. These data combined with the ciprofloxacin data (Fig. 4) suggests the synergistic action of LxA₄ with antibiotics is dependent on the class of antibiotics and their mechanism of action. 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 < 0.05; CFUs n = 4 independent experiments; biofilm n = 3 (LxA₄ 1 nM) and n = 4 (LxA₄ 10 nM) independent experiments.