Figure 5.

The AIEC LF82 strain counteracts the anti-inflammatory effect of propionate in mice

CEABAC10 mice (n = 9, two independent experiments pooled) were pretreated with an antibiotic cocktail containing 500 mg/L metronidazole, 1 g/L streptomycin, 1 g/L neomycin and 1 g/L ampicillin. Mice received 1% DSS and, when needed, 0.6% calcium propionate in their drinking water in parallel with antibiotic treatment. On day 5, the antibiotic treatment was stopped; 0.25% DSS and 0.6% propionate were maintained in the drinking water. On day 6, mice were orally infected with AIEC LF82, the isogenic mutant LF82ΔprpC, or PBS as a control. (a) Disease activity index of mice. (b–d) Secreted KC chemokine, IL-6 and TNF-α cytokines amounts from colonic tissue of mice. (E) Propionate concentrations from fecal samples of mice before and after infection. The results are presented as the median values. Statistical comparisons were carried out by normality testing using Kolmogorov-Smirnov tests, and a subsequent one-way ANOVA with Bonferroni post hoc test was performed (a–d). A nonparametric Friedman test was applied to assess differences in propionate concentration before and after infection (e) (*p < .05, **p < .01, ***p < .001).