Enhanced cultivation of Helicobacter pylori in liquid media

Abstract

Aims-To evaluate a technique for culture of Helicobacter pylon in large quantities of liquid media and to determine the factors that could influence the results. Methods-Fifteen clinical isolates of H pyloni and a reference strain of H pyloni NCTC11637 were used to evaluate a method to cultivate the organism in 100 ml liquid medium comprising brain heart infusion broth with 5% horse serum and 0-25% yeast extract. Tissue culture flasks containing the inoculated liquid medium were placed in a CO, incubator with 5% CO2 for 2 hours and then incubated in a shaking incubator at 120 rpm. Results-All the clinical isolates and the reference strain grew in the broth, although only a moderate growth of the reference strain occurred. Inoculum size significantly influenced the kinetics of growth ofHpylon in the liquid medium. Vancomycin, nalidixic acid, and amphotericin B, used to suppress contamination, did not affect growth of Hpylori in the medium. CO2 was essential for H pyloni to grow or survive in the liquid medium. Incubation with CO2 in a CO2 incubator for 30 minutes or 2 hours did not affect the results. Conclusions-H pyloni can be cultivated in large quantities of brain heart infusion broth with 5% horse serum and 025% yeast extract. Initial inoculum concentrations influence the kinetics ofHpylori growth in the liquid medium. Vancomycin, nalidixic acid, and amphotericin B can be used as selective antimicrobial agents. CO 2 is essential for initial growth ofHpyloni in liquid media. The findings in this study may provide a useful, reproducible, and simple method for biochemical, molecular, and physiological studies of H pyloon, when those require large quantities of the organism.