Nontoxic ST28 streptococcus suis and application thereof

Abstract

The invention relates to a nontoxic ST28 streptococcus suis and an application thereof, and belongs to the biotechnology field. A tonsil sample of a healthy slaughter pig is collected; after bacteria enrichment processing, bacteria DNA (deoxyribonucleic acid) is extracted; a cps2j gene is identified by polymerase chain reaction; then, pure culture bacteria can be obtained by bacteria plate separation; the pure culture bacteria is subjected to gram stain, serum agglutination, polymerase chain reaction and multilocus sequence typing to determine and separate type-2 bacterial strain of the streptococcus suis and a sequence type thereof; animal experiments of a Balb / c mice, a New Zealand rabbit and a Landrace piglet prove that the bacteria HA0609 is a nontoxic bacterial strain; after the bacteria is subjected to intramuscular injection into the New Zealand rabbit for one time and is subjected to intraperitoneal injection into a CD1 mice for two times, certain immunocompetence can be provided for an immunized animal, and analysis on a HA0609 immune protection antigen can be used for developing streptococcus suis disease subunit vaccine.

Description

technical field [0001] The present invention relates to a non-toxic ST28 Streptococcus suis and application thereof, specifically a non-toxic ST28 Streptococcus suis ( Streptococcus suis ), and the application of the bacterium in the development of Streptococcus suis vaccine belong to the field of biotechnology. Background technique [0002] Streptococcus suis type 2 ( Streptococcus suis serotype 2, S. suis 2) It is an important zoonotic pathogen, which can cause meningitis, sepsis, arthritis and other symptoms in pigs, and the fatality rate is as high as 40%. If it is complicated with porcine respiratory and reproductive syndrome, the mortality rate is higher, even if the disease The pigs that can survive after that grow slowly, and the feed-to-meat ratio increases, which brings great economic losses to the pig industry, so the bacteria is a potential threat to the global pig production. S. suis 2. It can infect people through wounds and digestive tracts. In 1998 an...

AI Technical Summary

Problems solved by technology

[0003] According to the concept of "prevention instead of treatment" of animal epidemics, immunization vaccines are the key to the prevention and control of streptococcal suis. Traditional vaccines include inactivated vaccines and live attenuated vaccines. The advantages of inactivated bacterial vaccines and inactivated vaccines are that they are easy to produce, stable, and easy to store. The disadvantages are that multiple immunizations are required, the immunization dose is large, and the immune site is damaged.

The advantage of the live attenuated vaccine is that it only needs to be vaccinated once, the dose is small, and the immune protection period is long. The disadvantage is that it is unstable, difficult to store, and the virulence may relapse

The above two types of vaccines are bacterial vaccines, and the antigen composition is relatively complex. In addition to the protective antigen, it may contain more ineffective antigens, and the existence of ineffective antigens will interfere with the body’s response to the protective antigens, and sometimes cause serious side effects

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