The AaaA deficient mutant is less virulent in the chronic mouse wound model.

<p>Either the <i>P. aeruginosa</i> wild type PAO1 (black bars), the Δ<i>aaaA</i> mutant (white bars), or the complemented Δ<i>aaaA</i> mutant PAJL2 (grey bars) was inoculated (10⁴ CFU) into a chronic wound in each of 9 mice. After 2 (3 mice per group) or 8 (7 mice per group) days, wound tissue was removed and the bacterial load was estimated by calculating the colony forming units (<b>Panel A</b>). Chronically-wounded mice were euthanized at post infection day 2 (3 mice per group) or day 8 (7 mice per group), and wound tissue was harvested for qRT-PCR to detect the mRNA of the indicated cytokines and other host enzymes in the infected wound tissue as described in the <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1002854#s4" target="_blank">materials and methods</a> (<b>Panel B and C</b>). Tissue from the wounds of the 2 day infected mice (<b>Panels D,G,J</b>) or 8 day infected mice (<b>Panels E,F,H,I,K,L</b>) was stained with H&E and is shown at 100× magnification. Images of the <i>P. aeruginosa</i> wild type PAO1 (<b>Panels D,E,F</b>), Δ<i>aaaA</i> mutant (<b>Panels G,H,I</b>), and the complemented Δ<i>aaaA</i> mutant PAJL2 (<b>Panels J,K,L</b>) are shown with infiltrating neutrophils indicated by white arrows, elongated fibroblasts with a red arrow, single bacterial cells with white arrow heads and clumps of bacteria with a white asterisk. <b>Panels D–E,G–H,J–K</b> are representative of the wound site and <b>Panels F,I,L</b> are representative of the site of infection below the wound.