Six days following C. jejuni infection, the pathogen loads were determined in samples from the stomach, duodenum, ileum, and colon and furthermore, in ex vivo biopsies taken from the MLN, liver, kidneys, lungs, and spleen by culture as described earlier [15 (link)]. In brief, respective samples were homogenized in sterile PBS (Thermo Fisher Scientific, Waltham, MA, USA) with a sterile pestle, serial dilutions plated onto karmali agar (Oxoid, Wesel, Germany) and incubated under microaerophilic conditions for at least 48 h and 37 °C. The detection limit of viable pathogens was 100 CFU per g (CFU/g). In order to assess systemic spread of C. jejuni, thioglycollate enrichments broths (BD Bioscience, Heidelberg, Germany) were inoculated with approximately 200 µL of cardiac blood upon necropsy, incubated at 37 °C for one week and streaked onto karmali agar (Oxoid, Wesel, Germany) for further cultivation of C. jejuni [15 (link), 25 ]. The bacterial translocation frequencies were calculated by the percentage of C. jejuni culture-positive samples out of the total number of analyzed samples taken from respective organ of mice (in %).