Cultivation of Wild-type H. pylori Strains

The wild-type H. pylori strains Gam94-24, N6, P1, 26695, PMSS1, 7.13, TN2-GF4, and Sat464 were typical type-I isolates expressing CagA (Supplementary Table S1). The bacteria were grown on horse serum gonococcal (GC) agar plates containing vancomycin (10 μg/mL), nystatin (1 μg/mL), and trimethoprim (5 μg/mL), and in the case of mutants kanamycin (8 μg/mL), as described previously [73 (link),74 (link)]. Mutagenesis of the cagL gene was performed by insertion of a kanamycin resistance gene cassette as described [75 (link)]. All antibiotics were obtained from Sigma-Aldrich. Bacteria were grown at 37 °C for 2 days in an anaerobic jar containing a Campygen gas mix of 5% O₂, 10% CO₂, and 85% N₂ (Oxoid, Wesel, Germany) [76 (link),77 (link)].