Comparative Evaluation of Three Supplements for Helicobacter pylori Growth in Liquid Culture

Abstract

Helicobacter pylori, a microaerophilic fastidious bacterium, has been cultured on various plating and broth media since its discovery. Although the agar media can be sufficient for the identification, typing, and antibiotic resistance studies, no secretory antigen of H. pylori can be evaluated in such media. Thus, satisfactory growth of H. pylori in liquid culture which is needed for analysis of secretory proteins without the presence of interfering agents is in demand. We assessed the impact of beta-cyclodextrin, Fetal Bovine Serum (FBS), and charcoal as supplements for H. pylori growth. Furthermore, we aimed to identify the most favorable supplement that supports the secretion of the dominant secretory protein, vacuolating cytotoxin (VacA). Five clinical strains were cultured on broth media and the growth, viability, morphology, and protein content of each strain were determined. Our results revealed that beta-cyclodextrin supports the growth rate, viability, and cell lysate protein content to the extent similar to FBS. Application of beta-cyclodextrin is found to postpone spiral to coccoid conversion up to 72 h of incubation. Although FBS supports a higher VacA protein content, presence of interfering macromolecules in FBS questions its utility particularly for purposes of studying extra cellular proteins such as VacA. This study recommends further application of beta-cyclodextrin as a culture supplement with the potential capacity in neutralizing toxic compounds and flourishing the secretion of H. pylori proteins without addition of interfering proteins.

Diagnosis of Helicobacter pylori Infection

“…Not much progress has been made regarding culture this past year. It is, however, interesting to note that in a comparison of growth supplements for liquid culture, β cyclodextrin was found to be equivalent to fetal bovine serum in growth ability and viability, and in postponing the occurrence of coccoidal forms up to 72‐ hour incubation [11].…”

Phosphatidylethanolamine of Helicobacter pylori Functions as a Steroid-Binding Lipid in the Assimilation of Free Cholesterol and 3 -Hydroxl Steroids into the Bacterial Cell Membrane

“…For H. pylori in serum-free medium, the medium is supplemented with 2,6-di-O-methyl-␤-cyclodextrin (dM␤CD) as a growth-supporting factor (4,15). While the mechanism by which dM␤CD supports H. pylori growth remains unclear, an earlier study by our group demonstrated that dM␤CD protects H. pylori from the antimicrobial actions of unsaturated fatty acids and lysophosphatidylcholine (LPC) by inhibiting the binding of those lipophilic compounds to the cells of the organism (23).…”

Establecimiento de un Cepario de Helicobacter Pylori, Aislado de Biopsias Gástricas, Úlcera Péptica, Cáncer Gástrico y Personas Asintomáticas

“…Seguidamente, se observó un crecimiento inmediato superior por parte del medio Campylobacter sobre 5% FBS (suero fetal bovino), 0,2% b-cyclodextrina y BB (Brucella) teniendo en cuenta que a las 24 horas la diferencia de OD oscilaron entre 0,56 y 0,71 en medio Campylobacter; en cambio en los otros tres cultivos la diferencia de OD a las 24 horas osciló entre 0,1 y 0,6; siendo mayor en el medio liquido Campylobacter, pero en otro aspecto el decrecimiento fue mayor en Campylobacter ya que a las 48 horas entró en disminución de las OD; los valores oscilaron entre -0,46 y -0,82 a diferencia de los otros tres medios, los cuales a las 48 horas en cuatro cepas aún existió periodo de crecimiento que osciló entre 0,2 a 0,6 OD, las otras dos cepas mantuvieron un periodo de meseta (Douraghi et al, 2010). Finalmente a las 72 horas las cepas entraron en un periodo de decrecimiento mayor, las OD oscilaron entre -0,12 y -0,38 (Douraghi et al, 2010).…”

“…Finalmente a las 72 horas las cepas entraron en un periodo de decrecimiento mayor, las OD oscilaron entre -0,12 y -0,38 (Douraghi et al, 2010).…”