Fig. 1.

Clinical isolates display variable swarming phenotypes. Swarming plates (0.5 % agar M8) were incubated overnight at 30 °C and then at room temperature for 24–48 h. The colony morphology of clinical isolates varied, even among strains with identical twitching and swimming phenotypes. The laboratory strain PAO1 is at the bottom of each plate. (a) Swim-positive/twitch-negative; (b) swim-negative/twitch-positive; (c) swim-positive/twitch-positive; (d) swim-negative/twitch-negative. Enlarged views of colonies with small swarming diameters are provided in insets. Bars, 2 cm.