Fibrosis in C57bl/6 mice infected with S. typhimurium ΔaroA is variably penetrant. [A, B] Histological trichrome staining for collagen of uninfected [HBSS] and S. typhimurium ΔaroA-infected C57bl/6 mice in two independent experiments, C57-1 [A] and C57-5 [B], illustrating transmural fibrosis [blue staining] and distortion of tissue architecture by collagen infiltration. [C, D] Expression of αSMA protein in uninfected and infected mice from the same experiments, illustrating the differences in the αSMA response between the C57-1 [C] and C57-5 [D] experiments. Westerns were serially probed with GAPDH [glyceraldehyde 3-phosphate dehydrogenase] to control for protein loading differences. [E, F] Forest plots from a meta-analysis of nine independent S. typhimurium ΔaroA:C57bl/6 studies, illustrating the standardised mean differences [SMD] and 95% confidence intervals [CI] for αSMA protein expression [E] and COL1A1 gene expression [F]. Divergent studies C57-1 [pink] and C57-5 [blue] are highlighted. Random-effects modelling was used.