The distribution diagram of 10 sequenced B2 ExPEC pan-genome virulence genes among 46 <i>E. coli</i> strains.

<p>The uppermost row showed six classified clusters: 1, adhesins, green; 2, invasins, magenta; 3, iron acquisition/transport systems, blue; 4, polysialic acid synthesis, aquamarine; 5, toxins, purple; 6, others, darksalmon. Right side of the vertical line showed <i>E. coli</i> strains that were consistent with phylogenetic tree (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0112048#pone-0112048-g001" target="_blank">Figure 1</a>). The red and black body showed distribution of virulence genes among these strains. A red line meant that the virulence gene of interest was present at a particular strain, while a black line implied the gene was absent.