Survival of UPEC CFT073 (A) and 1177 (B) WT, mutant and complemented strains in whole blood killing assays.

<p>Bacteria were incubated in fresh whole blood for 3–5 h and colony counts were used to compare survival phenotypes of mutants and complemented strains to the WT parents. Fitness of the CFT073 and 1177 capsule (<i>kpsD</i>) mutants was significantly impaired compared to the WT, and was restored completely in the respective capsule complemented (<i>kpsD</i>^C) strains. The survival data for the RS218 WT derivatives could not be analyzed due to the high sensitivity of WT strain to killing by whole blood. <i>P</i> values, as determined by the independent samples, t test were as follows: # 0.038, * 0.042.