Fig. 2.

Ileal E. coli loads in recolonized gnotobiotic mice following ileitis induction. Gnotobiotic mice generated by quintuple antibiotic treatment were perorally recolonized with E. coli Nissle 1917 (EcN), E. coli K12 (EcK12), or a commensal E. coli (EcCo) strain as described in methods. Four days thereafter, E. coli recolonized mice (grey circles) were perorally infected with 100 cysts of Toxoplasma gondii in order to induce acute ileitis. With conventional microbiota recolonized (SPF; black circles) and gnotobiotic (GB; white circles) animals served as positive and negative controls, respectively. Indicated are E. coli loads within the ileal lumen at day 7 following ileitis induction determined by culture (CFU, colony forming units). Numbers of animals harboring E. coli out of the total number of analyzed animals are given in parentheses. Medians (black bars) and significance levels (p values) determined by the Mann–Whitney U test are indicated. Data shown were pooled from three independent experiments.