Fig. 5. K. oxytoca toxin production plays an intermediate role in disturbed but complex microbiota settings.
a, Ampicillin-treated SPF mice were colonized with K. oxytoca MK01 WT, sKO or left untreated 4 days before infection. On day 0, mice were orally infected with S. Typhimurium, and BWL and faecal colonization were monitored until day 2 p.i. Organs were sampled for examination of S. Typhimurium burden on day 2 p.i. Amp, ampicillin. b, Resulting BWL on day 1 and day 2 p.i. c, S. Typhimurium burden in the faeces on day 1 and day 2 p.i. d.p.i., days post infection. d, Corresponding levels of K. oxytoca MK01 WT or sKO in the faeces of the mice. DL, level of detection. e, Resulting CI of K. oxytoca MK01 WT and sKO colonized animals. P values indicated represent two-tailed Mann–Whitney U-test between WT and sKO or Wilcoxon matched-pairs signed rank test within each group comparing the different time points. f, Absolute quantification of faecal TM and TV at various time points of the experiment in MK01 WT and sKO colonized SPF-abx animals. g, Correlation of faecal TM levels and S. Typhimurium burden in the faeces on day 1 p.i. of K. oxytoca MK01 WT colonized mice. Pearson’s correlation coefficient R2 = 0.3088 and P = 0.0315 (two-tailed test). h, Colon length on day 2 p.i. i, Histological inflammation score of the proximal colon. Mean ± s.e.m. of one experiment with n = 4 (PBS) or n = 5 (WT/sKO) mice per group. j–l, Resulting S. Typhimurium burden in the lumen and tissue of the caecum and colon (j), the small intestine (k) and extra-intestinal organs including liver, spleen and mesenteric lymph nodes (MLN) (l). In b–h and j–l, mean ± s.e.m. of n = 3 experiments with n = 12 (PBS), n = 15 (WT/sKO) mice per group are displayed. P values indicated represent ordinary one-way ANOVA with Dunn’s multiple comparisons test (b, c, h and j–l) or two-tailed Mann–Whitney U-test (e and i) with *P < 0.05, **P < 0.01, ***P < 0.001 and ****P < 0.0001.