Enhanced cultivation of Helicobacter pylori in liquid media.
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.
Xia
H X
HX
Department of Clinical Microbiology, St James's Hospital, Dublin, Ireland.
English
L
L
Keane
C T
CT
O'Morain
C A
CA
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
D003470:Culture Media; D009268:Nalidixic Acid; D014640:Vancomycin; D000666:Amphotericin B