Streptococcus suis enrichment medium for high-density fermentation and preparation method of streptococcus suis enrichment medium

Abstract

The invention relates to the technical field of culture media, in particular to a streptococcus suis enrichment culture medium for high-density fermentation and a preparation method of the streptococcus suis enrichment culture medium. Tryptone; a soluble starch; glucose; sodium azide; a polymyxin B sulfate; l-cysteine hydrochloride is added; a buffer salt; an ion supplement; a cell wall relaxant; thiamine hydrochloride; an antioxidant; a composite nutrient source; an osmotic pressure regulator; growth factors. According to the culture medium, quick-acting glucose and slow-release starch are used for synergistically supplying energy, quick start and continuous metabolism are both considered, and the enrichment period is greatly shortened; polymyxin B is introduced to be combined with a sodium azide targeted inhibitor, so that gram-negative bacteria and part of positive infectious microbes are accurately inhibited, and the selectivity is remarkably improved; meanwhile, the activity of thalli is maintained by an anti-oxidation and buffer system, high-sensitivity detection of low-concentration samples is ensured, and the application scenario of efficient detection and industrial fermentation of streptococcus suis is conformed.

Description

Technical Field

[0001] The present invention relates to the technical field of culture media, and particularly to an enrichment culture medium for Streptococcus suis for high-density fermentation and a preparation method thereof. Background Art

[0002] An enrichment culture medium is a selective liquid medium, and its core function is to efficiently enrich specific pathogenic bacteria by providing appropriate nutrients and inhibiting the growth of non-target microorganisms. This culture medium is usually used in the pretreatment stage of complex samples, and can significantly improve the detection rate of target bacteria. Especially in the case of low initial bacterial load or serious interference from symbiotic microorganisms, its selective enrichment effect is crucial for subsequent separation and identification.

[0003] Traditional enrichment culture media for Streptococcus suis mostly take a basic nutritional formula as the core. For example, the brain heart infusion medium, whose typical components include animal tissue extracts, peptone, glucose and inorganic salts. Such culture media rely on natural components to provide growth factors and inhibit some miscellaneous bacteria through a single inhibitor, but their design is not deeply optimized for the metabolic characteristics of Streptococcus suis, and there is a lack of component regulation for high-density fermentation requirements.

[0004] Therefore, in the application of enrichment culture of Streptococcus suis for high-density fermentation, traditional culture media have three major limitations in high-density fermentation applications: First, the inhibition of symbiotic bacteria is not thorough, and miscellaneous bacteria with physiological characteristics similar to those of Streptococcus suis are likely to remain and compete for nutrients; second, the serotype adaptability is poor, and the different requirements of Streptococcus suis of different serotypes for carbon sources and vitamins lead to uneven proliferation efficiencies; third, the detection period is long and the sensitivity is insufficient. Traditional culture relying on natural proliferation takes more than 24 hours, and low-concentration samples are likely to be missed due to competitive inhibition or accumulation of metabolic by-products.

[0005] Based on this, the present invention provides an enrichment culture medium for Streptococcus suis for high-density fermentation and a preparation method thereof to solve the above-mentioned technical problems. Summary of the Invention

[0006] The purpose of the present invention is to provide an enrichment culture medium for Streptococcus suis for high-density fermentation and a preparation method thereof to solve the problems mentioned in the above background art.

[0007] To achieve the above purpose, the present invention provides the following technical solutions:

[0008] The present invention provides a enrichment medium for Streptococcus suis for high-density fermentation, comprising the following formulation in parts by mass: brain heart infusion powder: 20.0 - 30.0 parts; tryptone: 10.0 - 15.0 parts; soluble starch: 5.0 - 8.0 parts; glucose: 2.0 - 5.0 parts; sodium azide: 0.02 - 0.05 parts; polymyxin B sulfate: 0.01 - 0.03 parts; L-cysteine hydrochloride: 0.3 - 0.5 parts; buffer salt: 2.0 - 3.0 parts; ion supplement: 0.1 - 0.3 parts; cell wall relaxant: 0.5 - 1.0 parts; thiamine hydrochloride: 0.005 - 0.01 parts; antioxidant: 0.02 - 0.05 parts; complex nutrient source: 3.0 - 5.0 parts; osmotic pressure regulator: 0.05 - 0.1 parts; growth factor 5 - 10 parts, and the growth factor is horse serum, which is used to provide heme, coenzyme and unknown growth factors.

[0009] Preferably, the buffer salt is dipotassium hydrogen phosphate.

[0010] Preferably, the ion supplement is magnesium sulfate.

[0011] Preferably, the cell wall relaxant is glycine.

[0012] Preferably, the thiamine hydrochloride is vitamin B1.

[0013] Preferably, the antioxidant is glutathione.

[0014] Preferably, the complex nutrient source is yeast extract.

[0015] Preferably, the osmotic pressure regulator is calcium chloride.

[0016] The present invention also provides a preparation method of the enrichment medium for Streptococcus suis for high-density fermentation, comprising the following steps:

[0017] S1. Raw material weighing and pretreatment: In a sterile operating table at a temperature of 25 ± 2°C and a humidity ≤ 60%, use a precision electronic balance to weigh each raw material according to the formulation ratio: brain heart infusion powder: 20.0 - 30.0 parts, tryptone: 10.0 - 15.0 parts, soluble starch: 5.0 - 8.0 parts, glucose: 2.0 - 5.0 parts, dipotassium hydrogen phosphate: 2.0 - 3.0 parts, magnesium sulfate: 0.1 - 0.3 parts, glycine: 0.5 - 1.0 parts, calcium chloride: 0.05 - 0.1 parts, yeast extract: 3.0 - 5.0 parts; and separately pack the heat-sensitive components: polymyxin B sulfate: 0.01 - 0.03 parts, L-cysteine hydrochloride: 0.3 - 0.5 parts, glutathione: 0.02 - 0.05 parts, thiamine hydrochloride: 0.005 - 0.01 parts, horse serum: 5 - 10 parts; into dry and clean containers separately to avoid loss of activity caused by subsequent high-temperature sterilization;

[0018] S2. Mixing, Dissolving and Homogenization: Add 70% - 80% of sterile deionized water accounting for the total final volume into a stainless - steel stirring tank. After heating to 45 - 50 °C, sequentially add the weighed brain - heart infusion powder, tryptone, soluble starch, glucose, dipotassium hydrogen phosphate, magnesium sulfate, glycine, calcium chloride, and yeast extract. Turn on the magnetic stirrer and stir at a speed of 500 - 800 revolutions per minute for 30 - 45 minutes until all components are completely dissolved and there are no visible particles. Then adjust the pH of the solution to 7.2 - 7.4 and calibrate it in real - time with a pH meter to ensure the stability of the homogeneous mixture;

[0019] S3. High - temperature Sterilization and Cooling: Dispense the uniformly mixed solution into high - pressure - resistant glass bottles or fermenters and seal them. Place them in an autoclave, set the sterilization parameters as temperature 121 °C ± 1 °C, pressure 0.1 - 0.15 MPa, and time 15 - 20 minutes. Immediately start the circulating water cooling system after sterilization and cool down at a rate of 2 - 3 °C per minute to 40 - 45 °C to avoid precipitation of components or degradation of heat - sensitive substances caused by sudden temperature drop;

[0020] S4. Sterile Addition of Heat - sensitive Components: In a biosafety cabinet, pre - dispense polymyxin B sulfate, L - cysteine hydrochloride, glutathione, thiamine hydrochloride, and horse serum and pre - heat them to 35 - 37 °C through a constant - temperature water bath. Then add them to the cooled medium in sequence: polymyxin B sulfate: 0.01 - 0.03 parts, L - cysteine hydrochloride: 0.3 - 0.5 parts, glutathione: 0.02 - 0.05 parts, thiamine hydrochloride: 0.005 - 0.01 parts, horse serum: 5 - 10 parts; and gently stir with a magnetic stirrer at a speed of 200 - 300 revolutions per minute for 5 - 10 minutes to ensure that all components are fully mixed and no bubbles are generated.

[0021] Preferably, the adjusting solution in step S2 is one of 1M sodium hydroxide or 1M hydrochloric acid.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0023] The culture medium of the present invention uses rapid - acting glucose and slow - release starch to supply energy synergistically, taking into account rapid startup and continuous metabolism, and greatly shortening the bacteria - increasing cycle. Secondly, a combination of polymyxin B and sodium azide targeting inhibitors is introduced to precisely inhibit Gram - negative bacteria and some positive miscellaneous bacteria, significantly improving selectivity. In addition, through the synergistic effect of vitamin B1, L - cysteine metabolic activator and horse serum broad - spectrum growth factor, the proliferation efficiency of different serotype strains is enhanced. At the same time, an antioxidant and buffer system is used to maintain the activity of bacteria, ensuring high - sensitivity detection of low - concentration samples, and achieving an overall improvement in bacteria - increasing efficiency, selectivity and stability, which is in line with the high - efficiency detection and industrial fermentation application scenarios of Streptococcus suis. Detailed implementation manners

[0024] Next, in combination with the embodiments of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present invention.

[0025] I. Materials:

[0026] For the formula of the enrichment medium for Streptococcus suis used in high-density fermentation of the present invention, unless otherwise stated, they are all commercially available;

[0027] The present invention provides an enrichment medium for Streptococcus suis used in high-density fermentation, including the following formula in parts by mass: brain heart infusion powder: 20.0 - 30.0 parts; tryptone: 10.0 - 15.0 parts; soluble starch: 5.0 - 8.0 parts; glucose: 2.0 - 5.0 parts; sodium azide: 0.02 - 0.05 parts; polymyxin B sulfate: 0.01 - 0.03 parts; L-cysteine hydrochloride: 0.3 - 0.5 parts; buffer salt: 2.0 - 3.0 parts; ion supplement: 0.1 - 0.3 parts; cell wall relaxant: 0.5 - 1.0 parts; thiamine hydrochloride: 0.005 - 0.01 parts; antioxidant: 0.02 - 0.05 parts; complex nutrient source: 3.0 - 5.0 parts; osmotic pressure regulator: 0.05 - 0.1 parts; growth factor 5 - 10 parts, and the growth factor is horse serum, which is used to provide heme, coenzymes and unknown growth factors.

[0028] Among them, it should also be noted that the buffer salt is dipotassium hydrogen phosphate.

[0029] Among them, it should also be noted that the ion supplement is magnesium sulfate.

[0030] Among them, it should also be noted that the cell wall relaxant is glycine.

[0031] Among them, it should also be noted that thiamine hydrochloride is vitamin B1.

[0032] Among them, it should also be noted that the antioxidant is glutathione.

[0033] Among them, it should also be noted that the complex nutrient source is yeast extract.

[0034] Among them, it should also be noted that the osmotic pressure regulator is calcium chloride.

[0035] II. Processes:

[0036] Based on the above-mentioned formula components of the enrichment medium for Streptococcus suis for high-density fermentation, the present invention also provides a method for preparing an enrichment medium for Streptococcus suis for high-density fermentation, comprising the following steps:

[0037] S1. Raw material weighing and pretreatment: In a sterile operating table at a temperature of 25 ± 2°C and a humidity of ≤ 60%, use a precision electronic balance to weigh each raw material according to the formula ratio: brain heart infusion powder: 20.0 - 30.0 parts, tryptone: 10.0 - 15.0 parts, soluble starch: 5.0 - 8.0 parts, glucose: 2.0 - 5.0 parts, dipotassium hydrogen phosphate: 2.0 - 3.0 parts, magnesium sulfate: 0.1 - 0.3 parts, glycine: 0.5 - 1.0 parts, calcium chloride: 0.05 - 0.1 parts, yeast extract: 3.0 - 5.0 parts; and separately pack the thermosensitive components: polymyxin B sulfate: 0.01 - 0.03 parts, L-cysteine hydrochloride: 0.3 - 0.5 parts, glutathione: 0.02 - 0.05 parts, thiamine hydrochloride: 0.005 - 0.01 parts, horse serum: 5 - 10 parts; into dry and clean containers separately to avoid loss of activity caused by subsequent high-temperature sterilization;

[0038] S2. Mixing, dissolving and homogenization: Add 70% - 80% of sterile deionized water based on the total final volume to a stainless steel stirring tank, heat it to 45 - 50°C, and then sequentially add the weighed brain heart infusion powder, tryptone, soluble starch, glucose, dipotassium hydrogen phosphate, magnesium sulfate, glycine, calcium chloride, yeast extract, turn on the magnetic stirrer and stir at a speed of 500 - 800 revolutions per minute for 30 - 45 minutes until all components are completely dissolved and there are no visible particles, then adjust the pH of the solution to 7.2 - 7.4 and calibrate it in real time with a pH meter to ensure the homogenization and stability of the mixed solution;

[0039] S3. High-temperature sterilization and cooling: Sub-pack the uniformly mixed solution into high-pressure-resistant glass bottles or fermentation tanks and seal them, place them in an autoclave, set the sterilization parameters as temperature 121°C ± 1°C, pressure 0.1 - 0.15 MPa, time 15 - 20 minutes, immediately start the circulating water cooling system after sterilization, and cool down to 40 - 45°C at a rate of 2 - 3°C per minute to avoid precipitation of components or degradation of thermosensitive substances caused by sudden temperature drop;

[0040] S4. Sterile addition of heat-sensitive components: In a biosafety cabinet, pre-packaged polymyxin B sulfate, L-cysteine hydrochloride, glutathione, thiamine hydrochloride, and horse serum were preheated to 35 - 37°C in a constant temperature water bath, and then added to the cooled medium in sequence: polymyxin B sulfate: 0.01 - 0.03 parts, L-cysteine hydrochloride: 0.3 - 0.5 parts, glutathione: 0.02 - 0.05 parts, thiamine hydrochloride: 0.005 - 0.01 parts, horse serum: 5 - 10 parts; and gently stirred with a magnetic stirrer at a speed of 200 - 300 revolutions per minute for 5 - 10 minutes to ensure that each component was fully mixed and no bubbles were generated.

[0041] It should also be noted that the adjustment solution in step S2 is one of 1M sodium hydroxide or 1M hydrochloric acid.

[0042] Example 1, in this example, a method for preparing an enrichment medium for Streptococcus suis for high-density fermentation includes the following steps: Raw material weighing: Weigh according to the components in Example 1 in Table 1, and the heat-sensitive components are separately packaged;

[0043] Mixing and dissolving: Stir at 45°C for 40 minutes and adjust the pH to 7.3;

[0044] Sterilization and cooling: Sterilize at 121°C for 15 minutes and cool to 42°C;

[0045] Heat-sensitive addition: Add 0.02 g / L of polymyxin B sulfate, 0.4 g / L of L-cysteine hydrochloride, 0.03 g / L of glutathione, 0.008 g / L of thiamine hydrochloride, and 7.5% of horse serum in a biosafety cabinet and stir for 8 minutes;

[0046] Sub-packaging and detection: After sub-packaging, inoculate Streptococcus suis serotype 2 (initial concentration 10 2 CFU / mL), culture at 37°C, and monitor the enrichment time and OD600 value;

[0047] Example 2, in this example, the brain heart infusion powder is 20.0 g / L, and other process parameters are the same as those in Example 1;

[0048] Example 3, in this example, the brain heart infusion powder is 30.0 g / L, and other process parameters are the same as those in Example 1;

[0049] Comparative Example 1, in this example, the brain heart infusion powder is 15.0 g / L, and other process parameters are the same as those in Example 1;

[0050] Comparative Example 2, in this example, the polymyxin B sulfate is 0.0 g / L, and other process parameters are the same as those in Example 1;

[0051] The component parameters in Examples 1 to 3 are shown in Table 1:

[0052] Table 1 Parameter Table of Material Components in Examples

[0053] Ingredient Example 1 Example 2 Example 3 Brain heart infusion powder 25.0 20.0 30.0 Tryptone 12.5 12.5 12.5 Soluble starch 6.5 6.5 6.5 Glucose 3.5 3.5 3.5 Dipotassium hydrogen phosphate 2.5 2.5 2.5 Magnesium sulfate 0.2 0.2 0.2 Glycine 0.75 0.75 0.75 Calcium chloride 0.08 0.08 0.08 Yeast extract 4.0 4.0 4.0 Polymyxin B sulfate 0.02 0.02 0.02 L-Cysteine hydrochloride 0.4 0.4 0.4 Glutathione 0.03 0.03 0.03 Thiamine hydrochloride 0.008 0.008 0.008 Horse serum 7.5％ 7.5％ 7.5％

[0054] The component parameters of Comparative Examples 1 to 2 are shown in Table 2:

[0055] Table 2 Parameter Table of Material Components in Comparative Examples

[0056]

[0057]

[0058] The performance of the culture media prepared with the process parameters of the examples and comparative examples was tested. The test process included the enrichment time, OD600 value, heterobacteria inhibition rate, and false negative rate. The test process standard was as follows:

[0059] The enrichment time was determined by culturing at 37 °C until the OD600 value ≥ 1.0 after inoculating the standard strain of Streptococcus suis;

[0060] The OD600 value was detected using a spectrophotometer at a wavelength of 600 nm;

[0061] The heterobacteria inhibition rate was calculated by adding Escherichia coli (10 4 CFU / mL) to the culture medium and then calculating the survival rate;

[0062] The false negative rate was evaluated by detecting the proportion of low-concentration samples (10 1 CFU / mL) that were not detected continuously for 3 times;

[0063] The performance data of the culture media prepared according to Examples 1 to 3 are shown in Table 3:

[0064] Table 3 Performance Data Table of Examples

[0065]

[0066]

[0067] The performance data of the culture media prepared according to Comparative Examples 1 to 2 are shown in Table 4:

[0068] Table 4 Performance Data Table of Comparative Examples

[0069]

[0070] III. Performance Analysis:

[0071] As can be seen from Tables 1 to 4, the enrichment time of the examples (15.8 - 19.0 hours) is significantly shorter than that of the comparative examples (18.5 - 26.3 hours), and the OD600 value of the examples (1.30 - 1.70) is higher than that of the comparative examples (0.68 - 1.40), indicating a higher cell density. The inhibition rate of miscellaneous bacteria in the examples (95.2% - 98.9%) is better than that of the comparative examples (70.2% - 94.8%), and the false negative rate of the examples (1.8% - 6.3%) is much lower than that of the comparative examples (8.9% - 28.7%). Therefore, the formula ratio range in the examples of the present invention is scientific;

[0072] Also, in Example 1, 25.0 g / L of brain heart infusion powder provides sufficient nutrition and avoids inhibition at high concentrations. Comparing with Examples 2 / 3, 30.0 g / L is slightly better but has a higher cost. 3.5 g / L of glucose balances the rapid-acting and slow-release carbon sources, and 0.02 g / L of polymyxin B sulfate can effectively inhibit miscellaneous bacteria without affecting the activity of Streptococcus suis. When it was not added in Comparative Example 2, the false negative rate increased sharply. In summary, the comprehensive performance of the culture medium prepared in Example 1 of the present invention is the best, and it is the best embodiment of the present invention.

[0073] In the description of this specification, the descriptions referring to terms such as "one embodiment", "example", "specific example", etc. mean that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0074] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to the specific embodiments described. Obviously, many modifications and variations can be made according to the content of this specification. These embodiments are selected and specifically described in this specification to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and utilize the present invention well. The present invention is only limited by the claims and their full scope and equivalents.

Claims

1. A enrichment medium for Streptococcus suis for high-density fermentation, characterized in that, It includes the following formula in parts by mass: Brain Heart Infusion powder: 20.0 - 30.0 parts; Tryptone: 10.0 - 15.0 parts; Soluble starch: 5.0 - 8.0 parts; Glucose: 2.0 - 5.0 parts; Sodium azide: 0.02 - 0.05 parts; Polymyxin B sulfate: 0.01 - 0.03 parts; L-Cysteine hydrochloride: 0.3 - 0.5 parts; Buffer salt: 2.0 - 3.0 parts; Ion supplement: 0.1 - 0.3 parts; Cell wall relaxant: 0.5 - 1.0 parts; Thiamine hydrochloride: 0.005 - 0.01 parts; Antioxidant: 0.02 - 0.05 parts; Complex nutrient source: 3.0 - 5.0 parts; Osmotic pressure regulator: 0.05 - 0.1 parts; Growth factor 5 - 10 parts, and the growth factor is horse serum, which is used to provide heme, coenzyme and unknown growth factors.

2. The enrichment medium for Streptococcus suis for high-density fermentation according to claim 1, characterized in that, The buffer salt is dipotassium hydrogen phosphate.

3. A Streptococcus suis enrichment medium for high-density fermentation according to claim 1, characterized in that, The ion supplement is magnesium sulfate.

4. A Streptococcus suis enrichment medium for high-density fermentation according to claim 1, characterized in that, The cell wall relaxant is glycine.

5. A Streptococcus suis enrichment medium for high-density fermentation according to claim 1, characterized in that, The thiamine hydrochloride is vitamin B1.

6. The enrichment medium for Streptococcus suis for high-density fermentation according to claim 1, wherein, The antioxidant is glutathione.

7. A Streptococcus suis enrichment medium for high-density fermentation according to claim 1, characterized in that, The complex nutrient source is yeast extract.

8. A Streptococcus suis enrichment medium for high-density fermentation according to claim 1, characterized in that, The osmotic pressure regulator is calcium chloride.

9. The preparation method of the enrichment medium for Streptococcus suis for high-density fermentation according to any one of claims 1 to 8, characterized in that, It includes the following steps: S1. Raw material weighing and pretreatment: In a sterile operating table at a temperature of 25 ± 2°C and a humidity of ≤60%, use a precision electronic balance to weigh each raw material according to the formula ratio: Brain Heart Infusion powder: 20.0 - 30.0 parts, Tryptone: 10.0 - 15.0 parts, Soluble starch: 5.0 - 8.0 parts, Glucose: 2.0 - 5.0 parts, Dipotassium hydrogen phosphate: 2.0 - 3.0 parts, Magnesium sulfate: 0.1 - 0.3 parts, Glycine: 0.5 - 1.0 parts, Calcium chloride: 0.05 - 0.1 parts, Yeast extract: 3.0 - 5.0 parts; and separately pack the heat-sensitive components: Polymyxin B sulfate: 0.01 - 0.03 parts, L-Cysteine hydrochloride: 0.3 - 0.5 parts, Glutathione: 0.02 - 0.05 parts, Thiamine hydrochloride: 0.005 - 0.01 parts, Horse serum: 5 - 10 parts; into dry and clean containers separately to avoid loss of activity caused by subsequent high-temperature sterilization; S2. Mixing, dissolving and homogenization: Add 70% - 80% of sterile deionized water accounting for the total final volume to a stainless steel stirring tank, heat it to 45 - 50°C, and then sequentially add the weighed Brain Heart Infusion powder, Tryptone, Soluble starch, Glucose, Dipotassium hydrogen phosphate, Magnesium sulfate, Glycine, Calcium chloride, Yeast extract, turn on the magnetic stirrer and stir at a speed of 500 - 800 revolutions per minute for 30 - 45 minutes until all components are completely dissolved and there are no visible particles, then adjust the pH of the solution to 7.2 - 7.4 and calibrate it in real time with a pH meter to ensure the homogenization and stability of the mixed solution; S3. High-temperature sterilization and cooling: Dispense the well-mixed solution into high-pressure-resistant glass bottles or fermenters, seal them, place them in an autoclave, set the sterilization parameters as temperature 121°C ± 1°C, pressure 0.1 - 0.15 MPa, and time 15 - 20 minutes. Immediately start the circulating water cooling system after sterilization and cool down to 40 - 45°C at a rate of 2 - 3°C per minute to avoid precipitation of components or degradation of heat-sensitive substances caused by sudden temperature drop; S4. Sterile addition of heat-sensitive components: In a biosafety cabinet, pre-dispense polymyxin B sulfate, L-cysteine hydrochloride, glutathione, thiamine hydrochloride, and horse serum and preheat them to 35 - 37°C through a constant-temperature water bath. Add them to the cooled medium in sequence: polymyxin B sulfate: 0.01 - 0.03 parts, L-cysteine hydrochloride: 0.3 - 0.5 parts, glutathione: 0.02 - 0.05 parts, thiamine hydrochloride: 0.005 - 0.01 parts, horse serum: 5 - 10 parts; and gently stir with a magnetic stirrer at a speed of 200 - 300 revolutions per minute for 5 - 10 minutes to ensure that all components are fully mixed and no bubbles are generated.

10. The preparation method of a Streptococcus suis enrichment medium for high-density fermentation according to claim 9, wherein, The adjusting solution in step S2 is one of 1M sodium hydroxide or 1M hydrochloric acid.

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