Phase variation test method for salmonella H antigen

Abstract

The invention discloses a phase variation test method for the salmonella H antigen. O antigen serum agglutination reaction is carried out on a salmonella strain to be detected, first-phase and second-phase H factors are sequentially examined according to the grouping conditions of the O antigen, when only one phase is detected out, and the strain to be detected is not single-phase strain, the strain to be detected is defined to be the target strain, then the H factors with known phase and the target strain are added into sterile nutrient broth, thallus precipitate is collected in a centrifuge mode after culture, and bacterium suspension obtained after bacterium washing is used for slide agglutination examination of the H antigen with the phase to be detected. After phase variation, slide agglutination of the H antigen is high in speed, the phenomenon is obvious, the phase variation test method is small in interference, high in repeatability, large in the success rate, easy to operate, and high in feasibility and practicability.

Description

technical field [0001] The invention relates to a phase variation test method of Salmonella H antigen. Background technique [0002] Salmonella is an important zoonotic pathogen in public health, and its correct serotype is of great significance in the control of infectious diseases. At present, 2,500 serotypes of Salmonella have been detected, and more than 290 serotypes have been reported in my country. The serotype identification of Salmonella is relatively complicated, and its serotype is jointly determined by the O antigen, phase 1 and phase 2 H antigens (some have only one phase H factor), and the determination of H antigen is the main basis for Salmonella serotype. The H antigen is located on the flagella. It is an unstable protein antigen in nature and has strong specificity. Factors such as heating, drying, freezing or ethanol treatment can damage the structure of the flagella, resulting in the weakening of the H antigen, thus affecting the identification work. co...

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Problems solved by technology

Among them, the simple plate method is widely used because of its simplicity and convenience, but its obvious disadvantage is that the success rate is low; the glass tube method and the inverted tube method have certain requirements for materials, such as capillary tubes and small inverted tubes, and the operation is complicated

In addition, the above method uses nutrient agar or semi-solid soft agar as the substrate for the growth of the strain. The presence of agar inhibits the fluidity of the medium, which antagonizes the motility of the flagella, thereby hindering the restoration of H antigenicity.

In addition, Salmonella can break through the low-concentration agar and diffuse into the medium to grow, making it difficult to pick the bacteria. Therefore, when performing the H antigen slide agglutination test, the medium inevitably enters the serum droplets with the bacteria, and It cannot be completely dispersed, and the tiny solid medium particles are easily confused with serum agglutination particles, which seriously interferes with the determination of agglutination results

In addition, the agglutinates of the H antigen are flocculent and difficult to observe. In the experiment, it is often necessary to pick more bacteria to enhance the agglutination effect, which is contradictory to the purpose of reducing the interference of the solid medium

In view of the above reasons, the current phase variation test method has disadvantages such as large interference, low success rate, complicated operation, and time-consuming, and cannot meet the increasing needs of inspection work.

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