In Vitro and In Vivo Helicobacter pylori Cultivation

H. pylori reference strains ATCC 700392, ATCC 43504 (metronidazole-resistant), and ATCC 700684 (clarithromycin resistant) were purchased from the American Type Culture Collection and used in the in vitro antibacterial assays. The strains were grown in Blood Agar Base No.2 (OXOID) supplemented with 8% defibrinated horse blood (OXOID) in a humidified microaerobic incubator (85% N₂, 10% CO₂, 5% O₂) at 37 °C for 48–72 h. For certain experiments, bacteria were grown for 48–72 h at 37 °C in brain heart infusion broth (OXOID) supplemented with 4% fetal bovine serum (Gibco). For in vivo experiments, the CagA⁺ mouse colonizing strain pre-mouse Sydney Strain 1 (PMSS1) [20 (link),21 (link)], obtained from the French National Reference Center for Campylobacters & Helicobacters (www.cnrch.fr), was used. For infection inocula, H. pylori PMSS1 was grown on in-house selective Wilkins Chalgren agar plates [22 (link)] under microaerobic conditions and transferred to Brucella broth medium as described below.