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Live streptomycin-dependent Pasteurella multocida vaccine for the prevention of hemorrhagic septicemia
Abstract:
A type B Pasteurella multocida was used for the development of a streptomycin-dependent (StrD) vaccine. Pasteurella multocida R-473, a hemorrhagic septicemia strain, was mutagenized with N-methyl-N'-nitro-N-nitrosoguanidine to increase the likelihood of encountering a StrD mutant and was plated on agar containing 400 microgram of streptomycin/ml. Replica plating was used to differentiate dependent from resistant colonies. Mice and rabbits were vaccinated with a StrD mutant and 21 days later, were challenge exposed, along with unvaccinated controls, with the wild type R-473. Protection of greater than 4 logs was shown for the vaccinated mice. All vaccinated rabbits were protected and all nonvaccinated controls succumbed to a challenge exposure of 500 or 1,000 LD50.
Insights
A novel streptomycin-dependent (StrD) vaccine was developed from Pasteurella multocida. Vaccinated mice and rabbits showed significant protection against hemorrhagic septicemia, demonstrating vaccine efficacy.
Area of Science:
- Veterinary Microbiology
- Bacteriology
- Vaccine Development
Background:
- Hemorrhagic septicemia, caused by Pasteurella multocida, poses a significant threat to livestock.
- Existing vaccines may have limitations, necessitating the development of new strategies.
- Streptomycin-dependent (StrD) mutants offer potential as live attenuated vaccines.
Purpose of the Study:
- To develop and evaluate a streptomycin-dependent (StrD) vaccine candidate against Pasteurella multocida type B.
- To assess the efficacy of the StrD vaccine in laboratory animal models (mice and rabbits).
Main Methods:
- Pasteurella multocida R-473 (hemorrhagic septicemia strain) was mutagenized using N-methyl-N'-nitro-N-nitrosoguanidine.
- Streptomycin-dependent mutants were selected on agar containing 400 µg/ml streptomycin.
- Replica plating was employed to identify dependent colonies.
- Vaccinated and unvaccinated mice and rabbits were challenged with wild-type P. multocida R-473.
Main Results:
- Vaccinated mice demonstrated protection exceeding 4 logs against P. multocida challenge.
- All vaccinated rabbits were fully protected from lethal challenge.
- Unvaccinated control animals in both groups succumbed to the infection.
Conclusions:
- The developed streptomycin-dependent Pasteurella multocida vaccine is effective in protecting mice and rabbits against hemorrhagic septicemia.
- StrD mutants represent a promising approach for developing live attenuated vaccines against bacterial pathogens.
- This StrD vaccine strategy warrants further investigation for broader applications in animal health.