<i>C. jejuni</i> colonization along the gastrointestinal tract of mice with <i>T. gondii</i>-induced acute ileitis.

<p>Acute ileitis was induced in conventionally colonized 3-months-old C57BL/6 mice by oral infection with 100 cysts of <i>Toxoplasma gondii</i> ME49 strain. Four days following ileitis induction, mice were orally infected with <i>C. jejuni</i> strain ATCC 43431 as described in Methods. (<b>A</b>) At day 7 p.i. when <i>T. gondii</i> infected mice display severe ileitis (ILE) <i>C. jejuni</i> densities in distinct compartments of the gastrointestinal tract were determined by quantification of live <i>C. jejuni</i> in luminal samples taken from stomach, duodenum, ileum, and colon by cultural analysis (CFU, colony forming units; solid circles) and compared to control mice without ileitis (Con). (<b>B</b>) <i>E. coli</i> loads in luminal ileum samples of mice with <i>T. gondii</i>-induced acute ileitis (day 7 p.i.; open circles) were compared to naïve controls (open diamonds). (<b>C</b>) Relative translocation frequencies (%) of live <i>C. jejuni</i> 43431 ATCC (Cj, black bars) and <i>E. coli</i> (Ec, open bars) were determined in <i>ex vivo</i> biopsies of mesenteric lymphnodes (MLN), spleen, liver, and blood derived from mice with <i>T. gondii</i>-induced acute ileitis at day 7 p.i. by culture in enrichment broths. (<b>D</b>) A complex molecular analysis of the ileal microbiota composition was assessed in mice with <i>T. gondii</i>-induced acute ileitis at day 7 p.i. (ILE; solid circles) and compared to naïve control animals (N; open circles). Main gut bacterial groups were quantified by Real-Time-PCR analyses amplifying bacterial 16S rRNA variable regions and 16S rRNA gene numbers/ng DNA derived from luminal ileal samples: <i>Enterobacteriaceae</i> (EB), Enterococci (EC), Lactic acid bacteria (LB), <i>Bifidobacteria</i> (BIF), <i>Bacteroides/Prevotella</i> spp. (BP), <i>Clostridium leptum</i> group (CLEP), <i>Clostridium coccoides</i> group (CLOCC), Mouse intestinal bacteroidetes (MIB), and total eubacterial load (TL). Numbers of animals harboring <i>C. jejuni</i> or <i>E. coli</i> out of the total number of analyzed animals are given in parentheses. Medians (black bars), standard deviations and significance levels (<i>P</i>-values) determined by Mann-Whitney-U test are indicated. Data shown were pooled from at least three independent experiments.