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In vitro and in vivo studies of streptomycin-dependent cholera vibrios
Abstract:
Streptomycin-dependent cholera vibrio strains were derived from Inaba, Ogawa, and NAG vibrios by the method of Mel. These phenotypes grew more slowly and attacked fermentable substances after a longer period of time than the streptomycin-sensitive parent strains. Rabbits injected with streptomycin-sensitive strains and their streptomycin-dependent forms showed homologous agglutinin production. Patas monkeys fed with 10(9) streptomycin-dependent strains shed them for 1 to 2 days without ill effect, whereas the same number of streptomycin-independent organisms caused disease. The possibility of the application of multiple doses of streptomycin-dependent organisms in oral immunization against cholera was considered.
Insights
Streptomycin-dependent cholera vibrio strains were developed and tested for oral immunization. These modified bacteria showed reduced virulence, offering a potential new strategy for cholera vaccines.
Area of Science:
- Microbiology
- Immunology
- Vaccinology
Background:
- Cholera remains a significant global health concern, necessitating novel vaccine development strategies.
- Streptomycin dependence offers a potential mechanism for attenuating virulent bacterial strains.
Purpose of the Study:
- To derive streptomycin-dependent strains of Vibrio cholerae.
- To evaluate the safety and immunogenicity of these streptomycin-dependent strains in animal models.
Main Methods:
- Derivation of streptomycin-dependent Vibrio cholerae strains from Inaba, Ogawa, and NAG serotypes using Mel's method.
- Assessment of growth characteristics and fermentation capabilities compared to parent strains.
- Evaluation of immune response (agglutinin production) in rabbits and pathogenicity in patas monkeys.
Main Results:
- Streptomycin-dependent strains exhibited slower growth and delayed fermentation compared to streptomycin-sensitive parent strains.
- Both streptomycin-sensitive and dependent strains induced homologous agglutinin production in rabbits.
- Oral administration of streptomycin-dependent strains to patas monkeys resulted in transient shedding without disease, unlike streptomycin-independent strains which caused illness.
Conclusions:
- Streptomycin-dependent cholera vibrio strains demonstrate reduced virulence.
- These findings suggest the potential application of streptomycin-dependent organisms in oral immunization strategies against cholera.