Characterization of H. pylori Strains

Two well-characterized cagA⁺, vacA s1/m1 H. pylori strains, originally isolated from human patients, were used in our experiments: the reference strain 60190 (kind gift from Dr. G. Perez-Perez, New York University, ATCC #49503 [65 (link)]), and strain PMSS1 (kind gift from Dr. K. Wilson, Vanderbilt University), which is widely used in murine infection experiments [66 (link)]. H. pylori strain 60190 was shown to be susceptible to metronidazole, amoxicillin, clarithromycin, levofloxacin, rifampicin and tetracycline [67 ], and strain PMSS1 was confirmed to be susceptible to metronidazole, amoxicillin, clarithromycin, and tetracycline in previous studies [68 (link),69 (link)]. For the experiments, bacteria were grown at 37 °C under microaerophilic conditions on Brucella agar plates, 5% sheep blood (Becton Dickinson) for 3 days. Colonies were harvested into warm Brucella broth supplemented with 10% FBS and were then cultured in a shaking incubator for a further 18 h period prior to use in the experiments.