Fig. 2

mcr-1 promotes colonization of the mouse intestinal tract, preserves microbiota composition, and reduces inflammation. Mice were challenged by oral gavage with E. coli mcr-1⁺ or with E. coli mcr-1^-. A The numbers of E. coli mcr-1⁺ or E. coli mcr-1^- were determined from the feces. Data are represented as means ± SEMs. B Intestinal microbiota composition was assessed from faecal 16S rRNA gene sequencing before E. coli mcr-1⁺ or E. coli mcr-1^- inoculation (Ninf) and at 3 days post-infection. The difference in composition measured by Jensen-Shannon and generalized UniFrac metrics are presented as nonmetric multidimensional scaling (NMDS) ordinations. In addition, Adonis tests were performed to assess significant differences in intestinal microbiota structure, and PermDisp2 was used to assess significant differences in dispersion within sample groups. The p values were adjusted for multiple group comparisons by the Benjamini-Hochberg (BH) procedure. C Fecal lipocalin-2 levels were measured by ELISA. Data are represented as means ± SEMs. NS indicates ‘not significant’