Generation of Abiotic Mouse Model

Female C57BL/6j mice were bred and maintained under SPF conditions in the Forschungsinstitute für Experimentelle Medizin (Charité – University Medicine, Berlin, Germany). Secondary abiotic mice with a virtually depleted microbiota were generated as described previously (Heimesaat et al., 2006 (link)). In brief, 8 weeks old mice were transferred into sterile cages and subjected to a broad-spectrum antibiotic treatment for 8 weeks by adding ampicillin plus sulbactam (1 g/L; Ratiopharm, Germany), vancomycin (500 mg/L; Cell Pharm, Germany), ciprofloxacin (200 mg/L; Bayer Vital, Germany), imipenem (250 mg/L; MSD, Germany) and metronidazole (1 g/L; Fresenius, Germany) to the drinking water (ad libitum). Cultural and culture-independent (i.e., 16S rRNA based molecular) quality control measures revealed virtual absence of bacteria in fecal samples as described earlier (Ekmekciu et al., 2017 (link)).