Allelic Exchange of H. pylori Virulence Factors

H. pylori strains J166 and PMSS1 are wild type human isolates that express the virulence factor cagA encoded within the cag pathogenicity island (cagPAI). Knockouts for cagA and cagY in these strains were constructed by an allelic exchange method as previously described [25 (link)]. All strains used for this study are listed in Table 1, along with their characteristics. Bacteria cultures were performed on brucella agar (BBL/Becton Dickinson, Sparks, MD) supplemented with 5% heat-inactivated newborn calf serum (Invitrogen, Carlsbad, CA) and TVPA antibiotics (trimethoprim, 5 mg/L; vancomycin, 10 mg/L; polymyxin B, 2.5 IU/L, amphotericin B, 2.5 mg/L (Sigma-Aldrich, St. Louis, MO). All H. pylori cultures were grown at 37°C under microaerophilic conditions of 5% O₂ generated by an Anoxomat (Advanced Instruments, Norwood, MA).