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Studies on Tyzzer's disease: isolation and propagation of Bacillus piliformia
Abstract:
Mice from a colony with subclinical Tyzzer's disease were treated with prednisolone in order to activate a Bacillus piliformis infection. From the livers of these mice the organism was isolated and serially passaged in embryonated eggs. It resisted heating at 75 degrees C for 20 minutes and was still infective after storage at -80 degree C for 24 days, but not for 52 days or more. Infectively was maintained for more than a year by storing infectious liver tissue at -190 degrees C. B. piliformis was also isolated from the liver of a mouse with naturally-occurring Tyzzer's disease and maintained for more than 300 passages. Mice inoculated with different egg passages developed fatal Tyzzer's disease and B. piliformis was reisolated from their livers.
Insights
Bacillus piliformis, the cause of Tyzzer
Area of Science:
- Veterinary Pathology
- Microbiology
- Infectious Diseases
Background:
- Tyzzer's disease, caused by Bacillus piliformis, is a significant concern in laboratory animal colonies.
- Subclinical infections can be activated by immunosuppression, posing a diagnostic challenge.
Purpose of the Study:
- To establish and characterize a method for culturing and maintaining Bacillus piliformis for research purposes.
- To assess the viability and infectivity of B. piliformis under various storage conditions.
Main Methods:
- Activation of subclinical Tyzzer's disease in mice using prednisolone.
- Isolation and serial passage of Bacillus piliformis in embryonated eggs.
- Assessment of organism viability after heat treatment and cryopreservation at -80°C and -190°C.
Main Results:
- Bacillus piliformis was successfully isolated and passaged in embryonated eggs.
- The organism remained infective after heating at 75°C for 20 minutes.
- Infectivity was maintained for 24 days at -80°C but not for 52 days.
- Cryopreservation at -190°C maintained infectivity for over a year.
- Over 300 passages were achieved from a naturally infected mouse liver.
Conclusions:
- Bacillus piliformis can be effectively cultured and maintained through serial passage in embryonated eggs.
- Specific storage conditions, particularly ultra-low temperatures, are crucial for long-term preservation of B. piliformis infectivity.
- This methodology facilitates the availability of viable B. piliformis for further research into Tyzzer's disease.