title: Enhanced cultivation of Helicobacter pylori in liquid media.
abstract: OBJECTIVE
  To evaluate a technique for culture of Helicobacter pylori in large quantities of liquid media and to determine the factors that could influence the results.
  
  
  METHODS
  Fifteen clinical isolates of H pylori and a reference strain of H pylori 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 CO2 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 of H pylori in the liquid medium. Vancomycin, nalidixic acid, and amphotericin B, used to suppress contamination, did not affect growth of H pylori in the medium. CO2 was essential for H pylori 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 pylori can be cultivated in large quantities of brain heart infusion broth with 5% horse serum and 0.25% yeast extract. Initial inoculum concentrations influence the kinetics of H pylori growth in the liquid medium. Vancomycin, nalidixic acid, and amphotericin B can be used as selective antimicrobial agents. CO2 is essential for initial growth of H pylori in liquid media. The findings in this study may provide a useful, reproducible, and simple method for biochemical, molecular, and physiological studies of H pylori, when those require large quantities of the organism.
authors.affiliation: Department of Clinical Microbiology, St James's Hospital, Dublin, Ireland.
authors.forename: H X
authors.initials: HX
authors.lastname: Xia
authors.forename: L
authors.initials: L
authors.lastname: English
authors.forename: C T
authors.initials: CT
authors.lastname: Keane
authors.forename: C A
authors.initials: CA
authors.lastname: O'Morain
mesh_terms: D000666:Amphotericin B / Q000494:pharmacology; D001431:Bacteriological Techniques; D015169:Colony Count, Microbial; D003470:Culture Media; D016480:Helicobacter pylori / Q000187:drug effects / Q000254:growth & development* / Q000378:metabolism; D006801:Humans; D009268:Nalidixic Acid / Q000494:pharmacology; D013997:Time Factors; D014640:Vancomycin / Q000494:pharmacology
chemical_list: D003470:Culture Media; D009268:Nalidixic Acid; D014640:Vancomycin; D000666:Amphotericin B