Figure 1

Isobologram analyses for tobramycin–bicarbonate combination against planktonic cells of P. aeruginosa (a, b) laboratory strain PAO1, and P. aeruginosa clinical cystic fibrosis isolates (c, d) 5914M (mucoid), (e, f) 3488D (dwarf) and (g, h) 3470C (classic). A strong synergistic-additive effect is observed against all four strains. Points along the isobologram represent the growth–no growth interface. (b, d, f, h) The orange shaded area represents the additive region and the green shade area represents the synergistic region.