Type II streptococcus suis sa1KR gene knockout mutant strain, preparation method and application thereof

Abstract

The invention relates to a gene knock-out mutant of Streptococcus suis type 2 salKR and the preparation method and the application thereof. The mutant 05ZYH33 delta salKR has the preservation number of CGMCC No.2259. The preparation method comprises a step of subjecting a dual signal transduction system in PAI89K pathogenicity island on chromosome 05ZYH33 of wild S.suis 2 strain to gene knock-out by homologous recombination technology. Verified by PCR identification and Southern blotting, the obtained stain is gene knock-out mutant named as 05ZYH33 delta salKR. Animal test shows that the mutant has no harm to animals, and the whole genome sequence of the mutant has large similarity to that of the wild strain, so that the mutant is suitable for research and production of vaccines.

Description

technical field [0001] The invention belongs to bacteria, and specifically relates to a preparation method of a type 2 Streptococcus suisserotype (Streptococcus suisserotype 2) salKR gene knockout mutant strain and its application in the development of Streptococcus suis disease vaccine. Background technique [0002] Streptococcus suis type 2 (S. suis2 for short) is an important zoonotic pathogen. Pigs are generally susceptible to S. suis 2, and infection can cause acute sepsis, pneumonia, meningitis, arthritis, endocarditis, and acute death. If not treated in time, the fatality rate can reach 40%. Growth is slow, and the storage time is greatly extended. In recent years, the prevalence of S. suis 2 in swine herds in southern provinces of my country has become increasingly serious, and large-scale outbreaks have occurred from time to time, causing economic losses of several billion yuan each year. The pathogen infects humans and can cause serious diseases such as meningiti...

AI Technical Summary

Problems solved by technology

The inactivated vaccine is an inactivated whole-bacteria dead vaccine. Its biggest advantage is that it is easy to prepare and produce, and it is stable and easy to store. The reaction is obvious, and some vaccines have poor protection

The advantage of the live attenuated vaccine is that it only needs to be vaccinated once, the inoculation dose is small, the immune effect is better, and the immunity is long-lasting; the disadvantage is that it is unstable, difficult to store, and virulence may reverse mutation

The above two vaccines are all bacteria-based vaccines, and their common disadvantage is that the antigen components injected into the body are many and complex, and many components are actually non-protective antigens

The existence of these non-protective antigen components interferes with the body's response to protective antigens (sometimes the response to non-protective antigens becomes the main response, while the protective antigen is a non-main response or even no response); The presence of antigens may bring about severe immune side effects, such as fever, immune diseases, etc.

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