Survival and fibrosis are host- and bacterial strain-dependent. [A] Kaplan-Meier survival estimates of CBA/J, 129S1/SvImJ [S1], or DBA mice infected with either wild-type S. typhimurium SL1344 or the ΔaroA mutant; 100% survival at Day 14 was observed in all three mouse strains infected with ΔaroA at Day 14 and CBA/J infected with SL1344 [blue, red, green, and orange lines]; 40% survival was observed in the SL1344-infected S1 mice by Day 14 [pink line]. None of the DBA animals infected with SL1344 survived Dast day 7 post infection [purple line]. [B, C] Trichrome staining of collagen, illustrating transmural tissue fibrosis and architectural distortion with concurrent tissue oedema in mice infected either with ΔaroA [B] or SL1344 [C] at Day 14 post infection. Due to high early mortality, the SL1344-infected DBA histology is from Day 7. [D, E] Western blots of αSMA protein expression in mice infected with ΔaroA [D] compared with SL1344 [E]. Low αSMA expression in the DBA and two of the five S1 mice reflects early-stage disease [before Day 8 post infection and rapid induction of αSMA protein expression]. [F] Quantification of αSMA protein expression normalised to GAPDH [glyceraldehyde 3-phosphate dehydrogenase] expression in ΔaroA- [■] or SL1344 [■]-infected mice. In CBA/J mice, SL1344 infection induced αSMA protein nearly 3-fold compared with ΔaroA infection; *p < 0.05.