Lactobacillus plantarum SY-25 and bacteriocin and application thereof

Abstract

The invention relates to the technical field of microorganism application, and particularly discloses lactobacillus plantarum SY-25 and bacteriocin and application of the lactobacillus plantarum SY-25, the lactobacillus plantarum SY-25 is preserved in China Center for Type Culture Collection on March 31, 2025, the preservation number is CCTCC NO: M 2025635, and the lactobacillus plantarum SY-25 is classified and named as lactobacillus plantarum SY-25. The lactobacillus plantarum SY-25 provided by the invention has an antibacterial broad spectrum property.

Description

Technical Field

[0001] The present invention relates to the technical field of microbial application, and in particular to a Lactobacillus plantarum SY-25, a bacteriocin and an application thereof. Background Art

[0002] Haemophilus parasuis ( Glaesserellaparasuis, G.parasuis ) is a Gram-negative, conditionally pathogenic bacterium that is widely present in the upper respiratory tract of pigs and is the main pathogen that causes Glasser's disease in pigs. Infection with Haemophilus parasuis is one of the main causes of high mortality in piglets on pig farms. It mainly harms weaned piglets aged 3 to 5 weeks and fattening pigs under 4 months old. The incidence rate is generally 10% to 15%, and the mortality rate can be as high as 50% or more. The fibrinous polyserositis, arthritis, and encephalitis caused by the disease will seriously endanger the health of pigs and increase the mortality rate of sick pigs, thereby causing huge economic losses to the pig industry. Currently, G. parasuis The main preventive measure for the disease is vaccination, and the main treatment measure is injection of antibiotics. G. parasuis The different antigenicity of capsular polysaccharides leads to a large number of serotypes, and the preventive effect of vaccines is limited. At the same time, the excessive use of antibiotics can lead to G. parasuis Drug resistance is increasing, and therefore, there is a need to find an alternative to antibiotics for H. parasuis infections. Summary of the Invention

[0003] To develop a product that can replace antibiotics for Haemophilus parasuis infections, the present invention provides a Lactobacillus plantarum SY-25, a bacteriocin thereof, and applications thereof. The Lactobacillus plantarum SY-25 provided by the present invention has broad-spectrum antibacterial activity, and the bacteriocin produced by it, as shown in SEQ ID NO. 1, has the function of inhibiting Haemophilus parasuis type 13.

[0004] The present invention provides a plant lactobacillus ( Lactobacillus plantarum ) SY-25, the plantarum Lactobacillus SY-25 was deposited in the China Center for Type Culture Collection on March 31, 2025, with a deposit number of CCTCC NO: M2025635, and was classified as Lactobacillus plantarum SY-25 Lactobacillus plantarum SY-25.

[0005] The Lactobacillus plantarum SY-25 provided by the present invention has a broad-spectrum antibacterial activity, and the bacteriocin produced by the Lactobacillus plantarum SY-25, whose amino acid sequence is shown in SEQ ID NO.1, has the function of inhibiting Haemophilus parasuis type 13.

[0006] The present invention also provides a bacterial liquid, which contains the Lactobacillus plantarum.

[0007] Furthermore, the number of viable bacteria in the bacterial solution is 1×107 CFU / mL~1×10 9 CFU / mL.

[0008] The present invention also provides a bacteriocin, the amino acid sequence of which is shown in SEQ ID NO. 1, and which is secreted by the Lactobacillus plantarum SY-25.

[0009] The present invention also provides an application of the plant lactobacillus SY-25, the bacterial solution or the bacteriocin in antibacterial treatment, wherein the antibacterial treatment is to inhibit any one or a combination of Staphylococcus aureus, Escherichia coli and Haemophilus parasuis type 13.

[0010] The present invention also provides a use of the Lactobacillus plantarum SY-25, the bacterial liquid or the bacteriocin in preparing a drug for treating or preventing Glasser's disease, which is caused by Haemophilus parasuis type 13.

[0011] Furthermore, the medicine is an injection preparation.

[0012] Furthermore, the drug is obtained by dissolving the bacteriocin shown in SEQ ID NO.1 in a solvent; The solvent is a buffer solution or an isotonic solution.

[0013] Furthermore, the isotonic solution is 0.9% by mass sodium chloride injection or 5% by mass glucose injection.

[0014] Compared with the prior art, the present invention has the following beneficial effects: The present invention separates and obtains a plant lactobacillus SY-25, which is effective against Staphylococcus aureus, Escherichia coli and type 13 G. parasuis All of them have significant antibacterial effects, and the inhibition zones are all larger than 20 mm.

[0015] A novel plantaricin SY-25 was extracted from Lactobacillus plantarum SY-25, the amino acid sequence of which is shown in SEQ ID NO. 1. The plantaricin SY-25 has a good inhibitory effect on Haemophilus parasuis type 13 and good stability, and can effectively prevent and treat Haemophilus parasuis disease.

[0016] Information on the deposit of biological materials SY-25, referred to as Lactobacillus plantarum SY-25 in this application, has been deposited in the China Center for Type Culture Collection on March 31, 2025, with the deposit number CCTCC NO: M 2025635. The depository address is Wuhan University, Wuhan, China, Postal Code: 430072, and is classified as Lactobacillus plantarum SY-25 Lactobacillus plantarum SY-25. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0018] Figure 1 The purified bacteriocin primary product of the present invention is type 13 G. parasuis Antibacterial effect; In the figure, A is the organic phase extraction of the primary bacteriocin product 13 G. parasuis Antibacterial effect; B is the aqueous phase extraction of the primary bacteriocin 13 G. parasuis Antibacterial effect.

[0019] Figure 2 The effect of different dextran gel column elution on the antibacterial activity of crude bacteriocin products; In the figure, A shows the effect of the crude bacteriocin product obtained by elution from a Sephadex G-25 gel column on the antibacterial activity; B shows the effect of the crude bacteriocin product obtained by elution from Sephadex G-50 gel column on the antibacterial activity.

[0020] Figure 3 This is a reverse-phase high-performance liquid chromatogram of bacteriocin.

[0021] Figure 4 This is the mass spectrum of bacteriocin produced by Lactobacillus plantarum SY-25; In the figure, A is the primary mass spectrum of bacteriocin produced by Lactobacillus plantarum SY-25; B is the secondary mass spectrum of the bacteriocin produced by Lactobacillus plantarum SY-25.

[0022] Figure 5 This is a Gram-stained plate image of Lactobacillus plantarum SY-25.

[0023] Figure 6 This is the PCR identification result of Lactobacillus plantarum SY-25, M is a marker, and 1 is Lactobacillus plantarum SY-25. DETAILED DESCRIPTION

[0024] The specific embodiments of the present invention are described in detail below, but it should be understood that the scope of protection of the present invention is not limited by the specific embodiments. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of the present invention. The experimental methods described in the embodiments of the present invention are conventional methods unless otherwise specified, and the materials, reagents, etc. used in the following embodiments can be obtained from commercial sources unless otherwise specified.

[0025] Example 1: Isolation and identification of Lactobacillus plantarum SY-25.

[0026] 1. Test methods 1. Strain Isolation In an ultra-clean workbench, take 100 μL of yogurt or a small amount of feed, add it to 900 μL of PBS, dilute it 10 times, and -4 100 μL of the solution was dropped onto an MRS plate and cultured overnight.

[0027] Gram staining: Use a sterile inoculating loop to pick up a single bacterial colony from a plate and dissolve it on a glass slide containing 5 μL of 0.9% NaCl. Evaporate the liquid to dryness before Gram staining. After the slide has air-dried, observe the bacterial morphology under a 100× oil-immersion microscope.

[0028] Probiotics with different colony morphologies were selected for multiple purification and amplification on solid culture medium. The purified probiotics were added to liquid culture medium for overnight culture. The appropriate culture medium and culture time were selected according to the concentration of the bacterial liquid for subsequent experiments.

[0029] 2. Strain identification DNA was extracted from the effective strains and used as a template for conventional PCR identification. The primers were based on Lactobacillus plantarum The PCR reaction was carried out using primers designed based on the SY-25 sequence, wherein the primer sequences are shown in SEQ ID NO. 2 to SEQ ID NO. 3.

[0030] Forward primer F: 5′-AGGCTGCCCCAGAAGAAG-3′ (SEQ ID NO. 2); Reverse primer R: 5′-AGTTGTAGCCGCCCCTGT-3′ (SEQ ID NO. 3).

[0031] 2. Experimental Results 1. Observation of bacterial morphology Depend on Figure 5We can observe that the bacterial colonies on MRS medium have smooth white surfaces and produce acid during growth. When the plate lid is opened, a distinct sour smell is emitted. They are Gram-positive and appear as short rods in pairs or linked together in chains, proving that they are Lactobacillus plantarum.

[0032] 2. Strain identification like Figure 6 As shown in the PCR identification results, the band is around 490bp and bright, proving that the bacterial type is single and not contaminated.

[0033] Example 2: Product analysis and application of Lactobacillus plantarum SY-25 isolated in Example 1.

[0034] 1. Test methods 1. Strain activation Lactobacillus plantarum SY-25 isolated and identified in Example 1 was spread on an MRS plate and cultured at 37°C for 24 hours. A single colony was picked and inoculated into MRS liquid medium and activated and cultured at 37°C for 12 hours to obtain a SY-25 bacterial solution. The SY-25 bacterial solution was inoculated into new MRS liquid medium at a 1% inoculum rate and activated and cultured at 37°C for 12 hours. This was repeated three times for later use.

[0035] Escherichia coli ( Escherichia coli ), Staphylococcus aureus ( Staphylococcus aureus ) and Haemophilus parasuis type 13 ( Glaesserella parasuis ) as indicator bacteria. Among them, Escherichia coli ( Escherichia coli ) was purchased from Henan Industrial Microbial Engineering Technology Company, No. BNCC337304. Staphylococcus aureus ( Staphylococcus aureus ) was purchased from the National Center for Medical Culture Collections (CMCC), number: CMCC(B)26003, and Haemophilus parasuis type 13 was isolated in the laboratory. Escherichia coli ), Staphylococcus aureus ( Staphylococcus aureus ) were inoculated into LB liquid medium, Haemophilus parasuis type 13 ( Glaesserella parasuis ) were inoculated into TSB medium at a rate of 1%, activated and cultured at 37°C for 12 h, and transferred three times for later use.

[0036] 2. Primary screening of crude products of bacteriocin produced by Lactobacillus plantarum SY-25 The activated SY-25 bacterial suspension was collected and centrifuged at 8000 rpm / min for 20 min at 4°C. The supernatant was collected and filtered through a 0.22 μm sterile filter to obtain the cell-free supernatant (CFS). The antibacterial test was performed using the agar diffusion method. The specific method is as follows:

[0037] 100 μL each of activated indicator bacteria Escherichia coli and Staphylococcus aureus were plated onto LB solid medium. 100 μL of activated indicator bacteria Haemophilus parasuis serotype 13 was plated onto TSA solid medium and spread evenly. A sterile hole punch was used to punch holes in a "pin" pattern on the surface of the solid medium. 200 μL of cell-free supernatant (CFS) was added to each hole. The plates were incubated at 37°C for 12 hours and then observed for diffusion. After the incubation period, the plates were removed and the diameters of the inhibition zones were measured using a vernier caliper. Each diameter was recorded and averaged.

[0038] 3. Rescreening of crude bacteriocin produced by Lactobacillus plantarum SY-25 (a) Elimination of organic acid interference: First, measure the pH of the cell-free supernatant (CFS) and adjust it with 1 mol / L NaOH to obtain the cell-free supernatant after the organic acid is eliminated. The cell-free supernatant (CFS) without organic acid elimination was used as a control. G. parasuis As an indicator bacteria, the agar diffusion method was used for antibacterial test, and the size of the inhibition zone was measured and recorded.

[0039] (b) Eliminate the interference of hydrogen peroxide: Add catalase to the cell-free supernatant (CFS) after removing organic acids to a final concentration of 0.5 mg / mL, filtered through a 0.22 μm filter, and incubate in a 37°C water bath for 2 h. G. parasuis For indicator bacteria, after coating a TSA plate, use a hole puncher to punch holes in a "pin" pattern. Add 200 μL of cell-free supernatant (CFS) that has been treated with organic acids and added with catalase to each well. Incubate at 37°C for 12 hours and observe the size of the inhibition zone. For a control group, repeat the coating and punching process. Add 200 μL of cell-free supernatant (CFS) that has been treated with organic acids but not treated with hydrogen peroxide to each well. Incubate at 37°C for 12 hours and observe the size of the inhibition zone. Observe the size of the inhibition zone on the two plates and compare them.

[0040] 4. Initial purification of crude bacteriocin product After removing the organic acid and hydrogen peroxide from the SY-25 CFS, add ethyl acetate in a 1:1 volume ratio. The mixture is then stirred at 4°C overnight and allowed to stand for 12 hours. Separation of the organic and aqueous phases will occur. The organic phase is transferred to a round-bottom flask and rotary evaporated at 40°C until no visible fluid is present. The round-bottom flask is then rinsed with 5 mL of PBS. The crude bacteriocin product is then filtered through a 0.22 μm filter, sealed with parafilm, and refrigerated at 4°C until ready for use. This yields the organic phase-extracted bacteriocin product.

[0041] 5. Repurification of crude bacteriocin product Prepare a Sephadex G-25 gel column with ultrapure water as the mobile phase at a flow rate of 0.2 mL / min. Equilibrate the column three times with the mobile phase. Keeping the injection surface moist, dispense 1 mL of CFS and rotate it 360 degrees along the side of the column to ensure that the initial bacteriocin product is evenly distributed over the gel. Then, turn on the constant flow pump to collect the sample, collecting 1.5 mL of sample per centrifuge tube. All collected samples are numbered, and the active fraction is screened using the agar diffusion method and stored in a refrigerator at 4°C to obtain the crude bacteriocin product.

[0042] 6. Bacteriocin purification final product and its structural identification The crude bacteriocin product was further purified using reversed-phase liquid chromatography (RP-HPLC). The product purified by reversed-phase liquid chromatography was pooled to obtain the final bacteriocin product, referred to as bacteriocin. 10% SDS was added to a final concentration of 1%, and the sample was incubated at 95°C for 5 minutes. The supernatant was collected and the protein was precipitated using TCA precipitation. The final bacteriocin product was analyzed using a Thermo UltiMate 3000 RSL Cnano nanoliter liquid chromatography tandem mass spectrometer (Q Exactive HF), acquiring data in DDA mode.

[0043] 7. Bacteriocin stability test (1) Temperature stability The stability of the bacteriocin at different temperatures was tested. The bacteriocin was subjected to a temperature gradient of 20°C, 40°C, 60°C, 80°C, and 121°C for 15 minutes at each temperature to observe the effect of temperature on the bacteriocin and evaluate its temperature stability.

[0044] (2) UV stability Different UV irradiation times were set: 20 min, 40 min, 60 min, 120 min, and 240 min. The effects of different UV irradiation conditions on the stability of bacteriocin were observed and the UV stability of bacteriocin was evaluated.

[0045] (3) pH stability The pH of the bacteriocin was adjusted from 3 to 12, and then its antibacterial activity was measured after stabilization at room temperature for 2 h. The effect of different pH conditions on the stability of the bacteriocin was observed and the pH stability of the bacteriocin was evaluated.

[0046] (4) Stability of heavy metal salts 5 mmol / L NaOH, MgCL2, CuSO4, KMnO4, and Fe2SO4 were added to the bacteriocin, and the heavy metal salt solution and bacteriocin were mixed in a 1:1 ratio. After mixing, the mixture was incubated at 37°C for 2 h and the antibacterial effect was observed. The effects of different heavy metal salt conditions on the stability of bacteriocin were observed, and the stability of bacteriocin heavy metal salts was evaluated.

[0047] (5) Surfactant stability Tween-20 and Tween-80 were added to the bacteriocin at a 1% (v / v) concentration, along with 0.1 mol / L EDTA and SDS at a 1:1 volume ratio. The mixture was mixed and incubated at 37°C for 2 h to observe the antibacterial effects. The effects of different surfactants on the stability of the bacteriocin were observed to evaluate the surfactant stability of the bacteriocin.

[0048] 8. Bacteriocin against type 13 G. parasuis preventive effect The experimental animals were female Kunming mice weighing 18-22 g, divided into 5 groups, with 6 mice in each group. The groups and treatments were as follows:

[0049] Blank control group: The experimental animals were rested for one week, and then injected with PBS once a day, 200 μL of PBS each time, for a total of 5 days.

[0050] Positive control group: experimental animals were kept in rest for one week, and challenged with Haemophilus parasuis type 13 at a dose of 3.0×10 9 CFU / mL.

[0051] Plantar lactobacillus group: The experimental animals were rested for one week, and then injected with plantar lactobacillus SY-25 once a day, 200 μL each time, with a bacteriocin injection dose of 6.98 mg / mL, for a total of 5 days.

[0052] Nisin group: The experimental animals were rested for one week, and then injected with nisin once a day, 200 μL each time, with a nisin dose of 5.0 mg / mL, for a total of 5 days.

[0053] The nisin was purchased from Shanghai MacLean Biochemical Technology Co., Ltd., CAS No.: 1414-45-5, MDL No.: MFCD00131724.

[0054] After the treatment of the above groups, the positive group, Lactobacillus plantarum group and Lactobacillus plantarum group were challenged with toxicity. The challenge dose of Haemophilus parasuis was 3.0×10 9 CFU / mL. Pathogenesis was observed 48 hours after challenge. Survival rate and liver bacterial load were also measured.

[0055] 9. Bacteriocin against type 13 G. parasuis Treatment effect The experimental animals were female Kunming mice weighing 18g to 22g, divided into 5 groups, with 6 mice in each group. The groups and treatments were as follows:

[0056] Blank control group: The experimental animals were rested for one week, and then injected with PBS once a day, 200 μL of PBS each time, for a total of 5 days.

[0057] Positive control group: experimental animals were kept in rest for one week, and challenged with Haemophilus parasuis type 13 at a dose of 3.0×10 9 CFU / mL.

[0058] Plantar lactobacillus group: The experimental animals were rested for one week and injected with bacteriocin once a day after the challenge, with each injection of 200 μL and a bacteriocin injection dose of 10 mg / mL for a total of 5 days.

[0059] Antibiotic group: The experimental animals were rested for one week, and then injected with nisin once a day, 200 μL each time, with an antibiotic dose of 5.0 mg / mL, for a total of 5 days.

[0060] 2. Test results 1. Preliminary screening of crude bacteriocin products produced by lactic acid bacteria Different lactic acid bacteria produced different antibacterial substances after culture, and the cell-free supernatant (CFS) after culture was used to determine the antibacterial effect. Among them, the average antibacterial diameter of Lactobacillus plantarum SY-25 against Staphylococcus aureus was 21.68±0.43 mm, the average antibacterial diameter against Escherichia coli was 23.22±0.26 mm, and the average antibacterial diameter against type 13 was 21.68±0.43 mm. G. parasuis The antibacterial effect was the best, with an inhibition diameter of 23.53 ± 0.25 mm. This indicates that the CFS produced by Lactobacillus plantarum SY-25 has a certain antibacterial effect against both Gram-negative and Gram-positive bacteria. The results are shown in Table 1.

[0061] 2. Rescreening results of crude bacteriocin products produced by lactic acid bacteria The results showed that the CFS produced by Lactobacillus plantarum SY-25 still had antibacterial activity even after the removal of organic acids and hydrogen peroxide, indicating that in addition to producing organic acids, hydrogen peroxide, and other substances, this bacteriocin may be a bacteriocin. The results are shown in Table 2.

[0062] 3. Initial purification of crude bacteriocin product After CFS was extracted and concentrated with ethyl acetate, the volume was reduced to 10 times of the original volume, with 5 mL remaining. The concentrated organic phase and the concentrated aqueous phase were collected separately.

[0063] The results are as follows Figure 1 As shown in the figure, after extraction, the diameter of the inhibition zone of CFS after organic phase treatment reached 28.97±1.45 mm, and that of CFS after aqueous phase treatment was 15.37±0.57 mm. This shows that CFS after organic phase extraction has an inhibitory effect on type 13 G. parasuis The CFS after aqueous extraction also has a certain antibacterial effect. This is due to incomplete extraction. Due to excessive impurities in the aqueous phase, the organic phase concentrated product was finally selected for the next step.

[0064] 4. Repurification of crude bacteriocin product After CFS was extracted with ethyl acetate and crudely purified and concentrated, it was passed through Sephadex G-25 and Sephadex G-50 gels to obtain various components. 50 tubes of eluate were collected from each group, and the antibacterial activity of these 100 tubes of eluate was observed by agar diffusion method. Among them, the Sephadex G-25 group had strong antibacterial activity in tubes 15-22, and the antibacterial activity of tube 19 was the strongest, reaching 27.90 mm; the Sephadex G-50 group had strong antibacterial activity in tubes 15-19, and tube 18 had the strongest antibacterial activity, and its antibacterial diameter reached 18.90 mm. The results are shown in Figure 2 .

[0065] 5. Purification of the final product of bacteriocin and its structural identification The bacteriocin was further purified by reversed-phase high performance liquid chromatography, and the concentration of mobile phase A was reduced to 10% ACN + 0.1% TFA. The elution curve was as follows: Figure 3 The effluent from this peak was collected and tested by agar diffusion method, which showed antibacterial activity. The ACN was removed by rotary evaporation and the product was stored in a refrigerator at 4°C until use.

[0066] After LC-MS mass spectrometry detection, the original result RAW file is obtained, and after comprehensive analysis by software such as XReport and Xcalibur, the primary mass spectrum is obtained, such as Figure 4 A total of 87 protein data were intercepted, including 1 bacteriocin-related data with a relative molecular mass of 5.821 kDa. The peak was analyzed by secondary mass spectrometry to obtain the secondary mass spectrum, as shown in the figure below. Figure 4B. The secondary structure of the bacteriocin was further analyzed using PEAKSStudio 7.0 software, and the amino acid sequence of the bacteriocin was obtained as shown in SEQ ID NO.1, with a relative molecular mass of C52H81N17O22. No matching sequences were found when comparing its amino acid sequence in databases such as GenBank, UniProt, and BLAST. Further comparison in the antimicrobial peptide database APS also did not find a matching sequence, indicating that the bacteriocin is a new type of plantaricin. According to the nomenclature rules for new bacteriocins in APS, the bacteriocin was named Plantaricin SY-25. The results are shown in Figure 4

[0067] SEQ ID NO. 1: QDDESDVPHVR (Glutamine-Aspartic Acid-Aspartic Acid-Glutamic Acid-Serine-Aspartic Acid-Valine-Proline-Histidine-Valine-Arginine).

[0068] 6. Bacteriocin stability test The results are shown in Table 3. The results of the bacteriocin stability test are as follows:

[0069] (1) pH stability: The plantaricin SY-25 solution was adjusted to different pH values. It was found that in the pH range of 2-7, the acidity and alkalinity had little effect on the stability of the bacteriocin, and the size of the inhibition zone was >25 mm. From pH 8, when the solution was alkaline, the inhibition zone began to shrink gradually until it reached a minimum inhibition zone of 9.23±0.56 mm at pH 12. (2) Stability of UV irradiation: As the UV irradiation time increases, the antibacterial effect does not change much. It just decays to a certain extent with the increase of time, but is relatively stable overall.

[0070] (3) Temperature stability: As the temperature continues to rise, the antibacterial ability of Plantaricin SY-25 decreases. At 121°C, the minimum inhibition zone is 12.1±0.23 mm. In terms of heavy metal salts, Fe 2+ 、Mn 2+ 、Zn 2+ Significant effect on the antibacterial effect of bacteriocin (++), Mg 2+ To a certain extent, the antibacterial effect is enhanced.

[0071] (4) Surfactant stability: Except for SDS, it was found that surfactants had little effect on Plantaricin SY-25, and the change in the inhibition zone was not obvious.

[0072] Note: ++++ indicates that the antibacterial diameter is ≥25 mm, +++ indicates that the antibacterial diameter is 15 < mm < 25, ++ indicates that the antibacterial diameter is 10 < mm ≤ 15, and + indicates that the antibacterial diameter is ≤10 mm.

[0073] 7. Bacteriocin against type 13 G. parasuis Prevention effect In the prevention test, plant lactobacillin and nisin played a good protective effect, making the bacterial load in the liver of these two groups much lower than that of the positive group; in terms of survival rate, the survival rate of the positive group was 33.3%, the survival rate of the plant lactobacillus group was 83.3%, and the rest were all 100%. The results are shown in Tables 4 and 5.

[0074] Note: ns indicates no difference from the positive group; * indicates a difference from the positive control group; ** indicates a significant difference from the positive group; *** indicates a highly significant difference from the positive group ( p <0.05) 8. Bacteriocin against type 13 G. parasuis Treatment effect Note: ns indicates no difference from the positive group; * indicates a difference from the positive control group; ** indicates a significant difference from the positive group; *** indicates a highly significant difference from the positive group ( p <0.01).

[0075] In the treatment test, the bacterial load in the liver of the plant lactobacillin group and the antibiotic group was extremely significantly lower than that of the positive group, indicating that plant lactobacillin and antibiotics had a treatment effect, laying a material foundation for reducing the use of antibiotics. In terms of survival rate, the survival rate of the positive group was 16.67%, and the rest were all 100%. The results are shown in Tables 6 and 7.

[0076] Although the preferred embodiments of the present invention have been described, those skilled in the art can make additional changes and modifications to these embodiments once they learn the basic creative concept.

[0077] Obviously, those skilled in the art can make various changes and deformations to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and deformations of the present invention fall within the scope of the claims of the present invention and its equivalent technologies, the present invention also intends to include these modifications and deformations.

Claims

1. A plant lactobacillus ( Lactobacillus plantarum )SY-25, characterized in that, The Lactobacillus plantarum SY-25 was deposited in the China Center for Type Culture Collection on March 31, 2025, with a deposit number of CCTCC NO: M2025635, and was classified as Lactobacillus plantarum SY-25. Lactobacillus plantarum SY-25.

2. A bacterial liquid, characterized in that: The bacterial liquid contains the Lactobacillus plantarum according to claim 1.

3. The bacterial solution according to claim 2, characterized in that The number of viable bacteria in the bacterial solution is 1×10 7 CFU / mL~1×10 9 CFU / mL.

4. A bacteriocin, characterized in that The amino acid sequence of the bacteriocin is shown in SEQ ID NO. 1, and is secreted by the Lactobacillus plantarum SY-25 according to claim 1.

5. Use of the Lactobacillus plantarum SY-25 according to claim 1, the bacterial solution according to any one of claims 2 to 3, or the bacteriocin according to claim 4 in antibacterial treatment, characterized in that: The antibacterial agent is any one or a combination of Staphylococcus aureus, Escherichia coli and Haemophilus parasuis type 13.

6. Use of the bacteriocin according to claim 4 in preparing a drug for treating or preventing Glaser's disease, characterized in that: Glasser's disease is caused by Haemophilus parasuis type 13.

7. The use according to claim 6, characterized in that The medicine is an injection preparation.

8. The use according to claim 7, characterized in that The drug is obtained by dissolving the bacteriocin shown in SEQ ID NO.1 in a solvent; The solvent is a buffer solution or an isotonic solution.

9. The use according to claim 8, characterized in that The isotonic solution is 0.9% by mass sodium chloride injection or 5% by mass glucose injection.

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