Fig 7. Induced enteric chitinase expression likely promotes entero-hematogenic bacterial translocation following burn injury in a mouse model of enteric colonization with PA14 strain.

Experimental design: (Step 1) Acidified drinking water was supplemented with chitosan (50mg/l) four weeks prior to experiments while controls continued to receive unsupplemented acidified water. (Step 2) 48 hours prior to burn injury, enteric colonization with PA14 strain of WT mice was performed (see S3 Fig). (Step 3) With burn injury (full thickness, dorsal skin fold, ~20% BSA), (A) the Kaplan–Meier estimator of survival suggested a higher incidence of lethal PA14 septicemia in animals pre-sensitized with chitosan in drinking water (Burn+PA14 v.s. Burn+PA14+ chitosan-pre-sensitized: n = 12, χ² = 0.39, P = 0.53, hazard ratio = 0.84). (B) Cell count of peritoneal lavage (mostly neutrophils) suggested burn-induced peritonitis due to enteric translocation of PA14 strain, with or without enteric chitinase induction. (C) Similarly, blood culture suggested burn-induced entero-hematogenic translocation of PA14 strain. (B & C: n≥10; mean±SD; *P<0.05; normalized to control)