Growth and morphological transformations of Helicobacter pylori in broth media

Abstract

Helicobacter pylori, a cause of peptic ulcer disease and certain types of gastric cancers, has usually been cultured on diverse agar-based media, resulting in a requirement for 2 to 4 days of growth at 37°C. We have developed a novel broth medium consisting of a base medium supplemented with 2% newborn calf serum, Mg 2؉ , Cu 2؉ , Fe 2؉ , Zn 2؉ , Mn 2؉ , and 1 mg of lysed human erythrocytes per ml. This medium supports rapid growth of H. pylori, with a doubling time of about 50 min. Optimal growth was obtained in a pH range higher than that supporting most other gram-negative bacteria (at pH 8.5). H. pylori cultured in this supplemented broth retains the spiral morphology seen in both histological sections and cultures from agar-based media and also retains a high urease activity. After 18 h in this broth, H. pylori transforms to a coccal form with a complete loss of urease activity. Previously these cocci have been reported to be senescent, since they could not be subcultured on agar medium. Our experiments suggest that some of the cocci can revert back to the spiral morphology with full recovery of urease activity when subcultured in fresh microaerobic broth medium.

Distinction of Gastric Helicobacter spp. in Humans and Domestic Pets by Scanning Electron Microscopy

“…culture used for inoculation revealed that such morphological changes are reversible. This finding is congruent with the findings that coccoid forms maintain their antigenicity [36] and that they can revert back to the spiral morphology under appropriate conditions [35]. Infecting natural hosts with cultured Helicobacter spp.…”

Probing 23S Ribosomal RNA Cleavage Sites in Coccoid Helicobacter pylori

“…It has been suggested that coccoid H. pylori can revert back into the helical infective form and re-grow, provided that an appropriate environment is encountered [32]. The presence of polyphosphates as an energy and phosphorous source in coccoid H. pylori may permit a certain level of metabolism to preserve vital cellular functions such as transcriptional and translational processes [33].…”

Helicobacter pylori May Have Only a Transient Presence in the Oral Cavity and on the Surface of Oral Cancer

“…The morphological characteristics of H. pylori strains cultured with the culture supernatant of S. mutans or P intermedia were examined using phase contrast microscopy as described by Andersen et al (1). Coccal cell numbers of H. pylori when cultured in the oral bacterial culture supernatant were significantly higher than those in the control.…”