Table 3.

Phenotype associated with swarming motility among twitch-positive/swim-positive isolates

	Quartile 1 (n=48)	Quartile 2 (n=35)	Quartile 3 (n=30)	Quartile 4* (n=41)
Swarming diameter†	0–0.09	0.1–0.3	0.31–0.69	>0.7
Biofilm formation‡	1.41	1.02	0.98	0.88
PopD secretion, median§	16	19	12	51
T3SS-positive||	25 (52 %)	18 (53 %)	15 (50 %)	35 (85 %)

*T3SS activity was increased in quartile 4 (P=0.001, Kruskal–Wallis).

†Swarming diameter is normalized relative to PAO1.

‡Biofilm formation is normalized relative to PAO1. Biofilm formation differs across quartiles (P=0.009, Kruskal–Wallis).

§Median expressed as percentage of PA103 control.

||Positive defined as ≥15 % of PA103 control.