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Egg passage of rodshaped and coccoid forms of Helicobacter pylori: preliminary studies
1Department of Clinical Microbiology, University Hospital, Uppsala, Sweden.
Background:
We used egg passage of bacteria stored in water to evaluate the culturability of the coccoid form of Helicobacter pylori, as a complement to the results obtained from various animal models. Egg passage was performed, as it is a simple, rapid, and well-characterized old method by which to culture and evaluate culturability of bacteria compared to experiments in animal models. Egg passage has been used in such experiments since 1938 for isolation and growth of, for example, Rickettsiae sp. and Chlamydia sp.
Materials And Methods:
The rod-shaped form of H. pylori was produced by plate cultures for 4 and 7 days. The coccoid form of H. pylori was produced by culture on agar plates for 10 days, followed by storage in water. These preparations then were inoculated into the yolk sac of differently aged fertilized eggs.
Results:
Positive culture was obtained from 14 of 17 eggs (82%) inoculated with rod-shaped H. pylori compared to 0 of 22 eggs (0%) inoculated with the coccoid form.
Conclusion:
Culturability of H. pylori is reduced when it converts into the coccoid form produced by starvation and age followed by storage in water for several weeks at room temperature. Egg passage did not raise the culturability of the coccoid form of H. pylori. Our study demonstrates some clear differences between fresh rods and stored cocci forms of H. pylori in terms of culturability when passed through eggs.
Insights
Egg passage culturability of Helicobacter pylori (H. pylori) was evaluated. The coccoid form of H. pylori showed significantly reduced culturability compared to the rod-shaped form, even with egg passage.
Area of Science:
- Microbiology
- Bacteriology
- Infectious Diseases
Background:
- Investigating Helicobacter pylori (H. pylori) culturability in its coccoid form.
- Utilizing egg passage as a complementary method to animal models for bacterial evaluation.
- Leveraging a historical and efficient technique for bacterial isolation and growth.
Purpose of the Study:
- To assess the culturability of the coccoid form of H. pylori using egg passage.
- To compare the culturability of rod-shaped and coccoid H. pylori.
- To determine if egg passage enhances the culturability of the coccoid H. pylori form.
Main Methods:
- Culturing rod-shaped H. pylori for 4-7 days and coccoid H. pylori for 10 days followed by water storage.
- Inoculating fertilized eggs' yolk sacs with both forms of H. pylori.
- Evaluating bacterial recovery and growth through positive cultures from egg passages.
Main Results:
- Rod-shaped H. pylori showed high culturability (82%) in eggs.
- Coccoid H. pylori, even after egg passage, yielded no positive cultures (0%).
- Egg passage did not improve the recovery rate of the coccoid H. pylori form.
Conclusions:
- H. pylori culturability significantly decreases upon conversion to the coccoid form due to starvation, aging, and water storage.
- Egg passage is ineffective in restoring or enhancing the culturability of stored coccoid H. pylori.
- Distinct differences exist in the culturability of fresh rod-shaped versus stored coccoid H. pylori when assessed via egg passage.