Lactobacillus plantarum and application thereof in preventing streptococcus mutans infection

Abstract

The invention discloses a strain of lactobacillus plantarum and an application of the lactobacillus plantarum in prevention of streptococcus mutans infection, and relates to the technical field of lactobacillus plantarum, and the preservation number of the lactobacillus plantarum W94 is CCTCC (China Center for Type Culture Collection) NO: M20242717. The separation and purification method comprises the following steps: adding 1mL of a normal human oral saliva sample into 9mL of sterile water, fully and uniformly shaking, and diluting; taking 100 [mu] L of the sample suspension with the dilution degree of 10-7 times, coating the MRS solid culture medium with the sample suspension, and performing inverted culture in an anaerobic incubator at 37 DEG C for 48 h; after a single bacterial colony grows on the flat plate, selecting the single bacterial colony for purification, and repeating the process for more than three times until a pure bacterial colony is cultured. The lactobacillus plantarum is subjected to various experiments after being separated and purified, and the experiments prove that the lactobacillus plantarum has the advantages of inhibiting the growth of streptococcus mutans, being high in acid resistance, having a broad-spectrum antibacterial effect, influencing the formation of a biological membrane and reducing the expression of a virulence gene, is easy to culture and purify, and has a relatively good application prospect.

Description

Technical Field

[0001] The invention relates to the technical field of microorganisms, in particular to a plant lactobacillus strain and application thereof in preventing streptococcus mutans infection. Background Art

[0002] Streptococcus mutans is a Gram-positive coccus. It is one of the most common streptococci in the natural oral flora and is one of the main components of dental plaque. Dental caries is a bacterial infection that occurs in the hard tissues of the teeth and has the highest incidence rate among oral diseases. Streptococcus mutans is the main pathogen of dental caries. It has a variety of transmission modes, including maternal transmission, paternal transmission and other horizontal transmission modes.

[0003] Dental caries is a chronic disease prevalent in the world. The disease is initiated by the accumulation of plaque biofilm on the tooth surface, which manifests as damage to the hard tissue of the teeth and even tooth loss. Streptococcus mutans is considered to be an important cariogenic bacterium. It has strong acid production and acid resistance and mainly relies on the biofilm state to survive. The formed biofilm provides a protective environment for its survival and greatly enhances the tolerance of the strain. Therefore, reducing biofilm formation provides the possibility of preventing the occurrence of dental caries. For decades, humans have used antibiotics in large quantities to fight bacterial infections. However, due to the protective structure of the biofilm, ordinary antibiotics cannot eradicate bacteria in the biofilm state;

[0004] Probiotics refer to live microorganisms that are beneficial to the host, mainly including some specific bacteria and yeasts. These microorganisms can help maintain intestinal health, promote digestion, enhance immunity, and may have a positive impact on overall health. The emergence of antimicrobial drugs worldwide has promoted the development of probiotic bacterial therapy. In recent years, many in vivo studies have shown that some probiotics, such as Lactobacillus rhamnosus LGG and Streptococcus salivarius M18, can reduce the risk of dental caries by inhibiting the biofilm formation of Streptococcus mutans;

[0005] Through the above analysis, the problems and defects of the existing technology are as follows: At present, there are no probiotic products specifically used to inhibit Streptococcus mutans on the domestic market. Therefore, there is great application potential in developing such probiotics and using them as daily food to reduce the degree of infection. Summary of the invention

[0006] The purpose of the present invention is to solve the shortcomings of the prior art and to propose a plant lactobacillus and its application in preventing mutans streptococcus infection.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] Application of a plant lactobacillus strain in preventing infection by Streptococcus mutans, wherein the plant lactobacillus strain is W94, and a method for separating and purifying the plant lactobacillus strain comprises the following steps:

[0009] Take 1 mL of normal human oral saliva sample and add it to 9 mL of sterile water, shake it thoroughly and dilute it;

[0010] Take 100 μL of the sample suspension diluted 10-7 times and spread it on MRS solid medium, and incubate it upside down in an anaerobic incubator at 37°C for 48 h;

[0011] After a single colony grows on the plate, pick the single colony for purification. Repeat this process three or more times until a pure colony is cultured.

[0012] Preferred: The experimental method for microbiological characteristics of Lactobacillus plantarum W94 comprises the following steps:

[0013] Lactobacillus plantarum W94 was inoculated on MRS solid medium, and the colony morphology, color and transparency were observed;

[0014] The staining characteristics of the bacteria were observed by Gram staining;

[0015] The growth characteristics of the bacteria were measured at a constant temperature of 37°C or under anaerobic conditions;

[0016] The lactic acid bacteria biochemical identification tube was used to identify the response of Lactobacillus plantarum W94 to 11 carbohydrates.

[0017] Further: The lactic acid bacteria biochemical identification tube carried out a carbohydrate fermentation test on Lactobacillus plantarum W94, and 11 carbohydrates including esculin and cellobiose were selected as reaction substrates.

[0018] Further: the preparation method of the sterile supernatant of Lactobacillus plantarum W94 comprises the following steps:

[0019] The revived Lactobacillus plantarum W94 was inoculated into MRS liquid medium and cultured anaerobically at 37°C for 48 h;

[0020] The fermentation supernatant was collected, centrifuged at 12000g for 10 minutes, filtered twice with a 0.22 μm filter membrane to obtain a sterile supernatant (CFS), and placed in a 4°C refrigerator for use.

[0021] As a preferred solution of the present invention: an experimental method for the effect of the sterile supernatant of Lactobacillus plantarum W94 on the growth of Streptococcus mutans comprises the following steps:

[0022] After taking out mutans Streptococcus UA159 from the -80℃ freezer and thawing, 100 μL was spread on TSA plates. After activation and passage three times, a single colony was picked and inoculated into TSB broth and cultured until OD600 reached 0.6.

[0023] Add 200 μL of mutans Streptococcus in the logarithmic growth phase to 10 mL of TSB semi-solid medium, mix well and pour on a TSA solid plate to form a double-layer agarose plate;

[0024] Use a 7-mm diameter hole puncher to punch holes in the double-layer agarose plate, and add 100 μL of CFS or MRS liquid culture medium to each well as a negative control;

[0025] After culturing in an anaerobic box at 37°C for 24 hours, the samples were diluted and spread in multiple proportions, the number of viable bacteria was calculated, and a growth curve was drawn.

[0026] As a further solution of the present invention: an experimental method for the effect of the sterile supernatant of Lactobacillus plantarum W94 on the biofilm formation of Streptococcus mutans comprises the following steps:

[0027] CFS and Streptococcus mutans cultured to the logarithmic phase were mixed in a 1:1 ratio and added to a 96-well plate, 200 μL was added to each well, and 5 groups were repeated, with 5 parallel controls in each group;

[0028] After culturing in an anaerobic box at 37°C for 24 h, the culture medium in the wells was discarded and PBS was added for washing three times;

[0029] Add 200 μL of 95% methanol to each well for 15 minutes, then discard the methanol and dry naturally at room temperature;

[0030] Add 200 μL of 1% crystal violet to each well for staining for 10 minutes, then rinse with PBS to remove excess dye and dry naturally at room temperature;

[0031] 160 μL of 33% glacial acetic acid was added to each well to dissolve the dye adhering to the bacteria, and 125 μL of the soluble dye was transferred from each well to a new 96-well plate, and the absorbance was measured at a wavelength of 630 nm.

[0032] As a further embodiment of the present invention: Lactobacillus plantarum W94 is able to utilize and decompose esculin, cellobiose, maltose, sucrose, sorbitol, inulin, raffinose, lactose, mannitol, salicin and sodium hippurate.

[0033] On the basis of the above scheme: the aseptic fermentation supernatant of Lactobacillus plantarum W94 has an inhibitory effect on Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa, and has a broad-spectrum antibacterial effect.

[0034] On the basis of the above scheme: CFS at 8% dilution can inhibit the growth of Streptococcus mutans.

[0035] A strain of Lactobacillus plantarum, whose taxonomic name is (Lactiplantibacillus plantarum) W94, which was deposited in the China Center for Type Culture Collection (CCTCC) on December 4, 2024, with a deposit number of CCTCC NO: M20242717, and the content of Lactobacillus plantarum is not less than 5.0×10 8 cfu / mL or 5.0×10 8 cfu / g.

[0036] The beneficial effects of the present invention are:

[0037] 1. the application of a plant lactobacillus in preventing mutans streptococcus infection, by separating and purifying plant lactobacillus and carrying out various experiments on it, learning through experiments that plant lactobacillus has the growth that inhibits mutans streptococcus, strong acid resistance, broad-spectrum antibacterial action, affects biofilm formation, the advantage of lowering virulence gene expression, it is easy to cultivate and purify simultaneously, has good application prospect, has outstanding performance in promoting health, has broad application prospect in preventing and treating dental caries caused by mutans streptococcus (S.mutans) infection and related dairy products, functional products and health products processing and production. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 The present invention provides a colony morphology diagram of Lactobacillus plantarum W94;

[0039] Figure 2 The embodiment of the present invention provides a Gram staining image of Lactobacillus plantarum W94;

[0040] Figure 3 The embodiment of the present invention provides a schematic diagram of the effect of the sterile supernatant of Lactobacillus plantarum W94 on the growth of Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa;

[0041] Figure 4 The embodiment of the present invention provides a schematic diagram of the effect of the sterile supernatant of Lactobacillus plantarum W94 on the growth of Streptococcus mutans;

[0042] Figure 5 The embodiment of the present invention provides a schematic diagram of the effect of the sterile supernatant of Lactobacillus plantarum W94 on the biofilm formation of Streptococcus mutans;

[0043] Figure 6 The present invention provides a schematic diagram of the effect of the sterile supernatant of Lactobacillus plantarum W94 on the genes related to biofilm formation of Streptococcus mutans. DETAILED DESCRIPTION

[0044] The technical solution of this patent is further described in detail below in conjunction with specific implementation methods.

[0045] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0046] The plant lactobacillus provided by the present invention is taxonomically named (Lactiplantibacillusplantarum) W94, which was deposited in the China Center for Type Culture Collection (CCTCC) on December 4, 2024, with a deposit number of CCTCCNO: M20242717, and the content of plant lactobacillus is not less than 5.0×10 8 cfu / mL or 5.0×10 8 cfu / g.

[0047] Embodiment 1:

[0048] Isolation and purification of Lactobacillus plantarum W94:

[0049] Take 1 mL of normal human oral saliva sample and add it to 9 mL of sterile water. After sufficient shaking, dilute it. Take 100 μL of the sample suspension with a dilution of 10-7 times and spread it on MRS solid culture medium. Incubate it upside down in an anaerobic incubator at 37°C for 48 hours. After a single colony grows on the plate, pick a single colony for purification. Repeat this process more than three times until a pure colony is cultured.

[0050] Embodiment 2:

[0051] Experiment on microbiological characteristics of Lactobacillus plantarum W94;

[0052] (1) Colony characteristics: The bacterium forms milky white colonies on MRS solid medium. The colony surface is smooth, moist, and has protrusions. The edges are neat, opaque, and do not produce pigment. See Appendix. Figure 1 .

[0053] (2) Staining characteristics: Gram-positive, blue in color, short rod-shaped with round ends under light microscopy, usually appearing alone or in pairs of short chains, see Appendix Figure 2 .

[0054] (3) Growth characteristics: The cells reached the late logarithmic phase after being cultured in MRS medium at 37°C under aerobic or anaerobic conditions for about 16 h.

[0055] (4) Carbohydrate fermentation test of Lactobacillus plantarum W94: Lactobacillus plantarum W94 biochemical identification tube (purchased from Hangzhou Microbiological Reagent Co., Ltd.) was used to identify the response of Lactobacillus plantarum W94 to 11 kinds of carbohydrates.

[0056] The results are shown in Table 1. In the 11 carbohydrate fermentation tests, Lactobacillus plantarum W94 was able to utilize, decompose and metabolize 9 carbohydrates, including esculin, cellobiose, maltose, salicin, sorbitol, sucrose, inulin, lactose and raffinose.

[0057] Table 1 Biochemical identification results of Lactobacillus plantarum W94

[0058]

[0059] The plant lactobacillus W94 of cryopreservation was inoculated in the MRS solid medium, cultured anaerobically at 37 ℃ for 48h, then after the MRS solid medium was subcultured for three times, a single colony was inoculated in the liquid MRS medium and cultivated for 24h, and then the culture solution of 1mL plant lactobacillus W94 was inoculated in the MRS liquid medium of 9mL pH=2 and pH=3 and a control group was set. Then, after 37 ℃ of anaerobically cultured for 3h, 100 μL was coated on the MRS solid medium after the multiple dilution, and the anaerobic culture was taken out after 48h. Finally, the viable count on the counting plate was calculated and its survival rate (see Table 2).

[0060] Survival rate = viable bacterial count on the plate after MRS treatment at pH = 2 or pH = 3 / viable bacterial count on the MRS plate × 100%.

[0061] Table 2 Determination of acid resistance of Lactobacillus plantarum W94

[0062]

[0063]

[0064] Embodiment 3:

[0065] Experiment on the effect of sterile supernatant of Lactobacillus plantarum W94 on the growth of Streptococcus mutans:

[0066] After Lactobacillus plantarum W94 was revived and passaged 2-3 times, it was inoculated into MRS liquid culture medium. After anaerobic culture at 37°C for 48 hours, the fermentation supernatant of Lactobacillus plantarum W94 was collected, centrifuged at 12000g for 10 minutes, filtered twice with a 0.22μm filter membrane to obtain a sterile supernatant (Cell-free supernatant, CFS), which was placed in a 4°C refrigerator for use. After the experimental strain mutans streptococcus UA159 was taken out of the -80℃ refrigerator and melted, 100μL was drawn and coated on the TSA plate. After activation and passage three times, a single colony was picked and inoculated in TSB broth and cultured until OD600 reached 0.6. 200μL of mutans streptococcus in the logarithmic phase was added to 10mL TSA semi-solid medium, mixed, and poured on the TSA solid plate to form a double-layer agarose plate. After solidification, a 7mm diameter puncher was used to punch holes in the double-layer agarose plate, and 100μL CFS was added to each hole. MRS liquid medium was used as a negative control; 0.05% chlorhexidine was used as a positive control. It was placed in a 37℃ anaerobic box for 24h. The next day, the diameter of the inhibition zone was measured by taking a photo. The results are shown in Table 3. The same method was used to detect that the aseptic fermentation supernatant of Lactobacillus plantarum W94 also had an inhibitory effect on Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa. The results are shown in Appendix Figure 3 , indicating that this plant lactobacillus has a broad-spectrum antibacterial effect.

[0067] Table 3 Antibacterial ability of the supernatant of aseptic fermentation of Lactobacillus plantarum W94

[0068]

[0069] Keep in a 4℃ refrigerator for later use. Take out the experimental strain Streptococcus mutans UA159 from the -80℃ refrigerator and melt it. Then, draw 100μL and spread it on a TSA plate. After activation and subculture 3 times, pick a single colony and inoculate it in TSB broth and culture it until OD600 reaches 0.6. Take out 400μL of the bacterial solution in the exponential growth period and inoculate it into a test tube containing 4mL of sterile supernatant with different dilution ratios. Set up a sterile supernatant blank control group and a positive control group containing only Streptococcus mutans. This time is recorded as time 0, and then anaerobically culture it at 37℃, and use the culture turbidity (OD600) as the growth indicator of Streptococcus mutans. Take 200μL of samples at different time points, measure the absorbance value at a wavelength of 600nm, and draw a growth curve (see Appendix). Figure 4 );

[0070] The results showed that CFS at 8% dilution could inhibit the growth of Streptococcus mutans.

[0071] Table 3 and Figure 3 The results showed that the fermentation product of Lactobacillus plantarum W94 provided by the present invention had a significant inhibitory effect on the growth of Streptococcus mutans.

[0072] Embodiment 4:

[0073] Experiment on the effect of sterile supernatant of Lactobacillus plantarum W94 on biofilm formation of Streptococcus mutans:

[0074] Sterile supernatant (CFS) and Streptococcus mutans cultured to the logarithmic phase were mixed in a ratio of 1:1 and added to a 96-well plate. 200 μL was added to each well. Five groups were repeated, and each group had five parallel controls. The wells with MRS liquid culture medium were used as negative controls. The plates were placed in an anaerobic incubator at 37°C for 24 hours. The culture medium in the wells was discarded, 200 μL PBS was added, and each well was washed three times. The PBS was discarded, 200 μL 95% methanol was added to each well, and fixed for 15 minutes. After discarding the methanol, the plates were left to dry naturally at room temperature. 200 μL 1% crystal violet was added to each well and stained for 10 minutes. Rinse with PBS to remove excess dye and dry naturally at room temperature. 160 μL 33% glacial acetic acid was added to each well to dissolve the dye adhering to the bacteria again. 125 μL soluble dye was taken from each well and transferred to a new 96-well plate, and the absorbance was measured at a wavelength of 630 nm (see Appendix). Figure 5 ).

[0075] Embodiment 5:

[0076] Experiment on the effect of sterile supernatant of Lactobacillus plantarum W94 on genes related to biofilm formation of Streptococcus mutans:

[0077] Sterile supernatant (CFS) and Streptococcus mutans cultured to the logarithmic phase were mixed in a ratio of 1:1 and added to a 24-well plate. MRS medium was used as a control, 1 mL was added to each well, and the plate was cultured in an anaerobic incubator at 37°C for 24 h. The supernatant was removed, and the biofilm was collected in a centrifuge tube, resuspended in PBS, centrifuged at 12000 rpm for 5 min, the supernatant was removed, and PBS was added for washing again. 200 μL of prepared lysozyme solution (1M Tri-Hcl, PH=8.0200 μL; 0.5M EDTA 40 μL; 12% Triton X-100 1 mL; 200 mg / mL Lysozyme 1 mL was added with water to make the volume 10 mL) was added, and the plate was shaken at 37°C for 30 min. 800 uL Trizol was added, and mRNA was extracted by Trizol method. The extracted total RNA was used as a template and TaKaRa kit (PrimeScript RT reagent Kit with gDNA) was used. cDNA was synthesized by using Eraser. First, 2 μL 8×gDNA Eraser Premix and 1 μg RNA were added to a PCR tube, and the mixture was supplemented to 16 μL with RNase-free water. The mixture was evenly mixed and placed in a PCR instrument for incubation at 42°C for 2 min. After completion, 4 μL 5×RT Premix was added and the operation was performed on ice. After adding various reagents, the mixture was oscillated and mixed. The PCR tube was placed in a centrifuge for a short centrifugation to allow the reaction solution to settle at the bottom of the tube. Reverse transcription was then performed in a PCR instrument. The reaction conditions were: 37°C for 10 min, 85°C for 5 sec, and the sample was stored at 4°C. After cDNA synthesis, real-time quantitative PCR analysis was performed. The 16S rRNA gene was used as an internal reference gene to detect the expression of virulence genes such as gtfB, gtfC and gtfD at the mRNA level. The primer sequences were shown in Table 4. PCR reaction system: 2×SGExcelFast SYBR Green 5μL, 0.4μL of upstream and downstream primers (10μmol / L), 1μL of DNA template (5μmol / L), RNase-free water to 10μL, PCR reaction conditions: 95℃3min; 95℃5s, 60℃30s, 60℃20s, a total of 40 cycles, fluorescence quantitative PCR instrument for fluorescence detection, set up 3 sets of replicates, and use 2-ΔΔCT method to calculate the relative expression of mRNA, see Appendix Figure 6 .

[0078] Table 4 Specific primers for real-time quantitative PCR

[0079]

[0080]

[0081] The above is a preferred specific implementation manner of the present invention, and the protection scope of the present invention is not limited thereto. Any modification, equivalent substitution and improvement made by any technician familiar with the field within the technical scope disclosed by the present invention in combination with the prior art or public common sense, within the spirit and principle of the present invention, shall be covered by the protection scope of the present invention.

Claims

1. Use of a strain of Lactobacillus plantarum for preventing Streptococcus mutans infection, characterized in that: The plant lactobacillus is W94, and the separation and purification method thereof comprises the following steps: Take 1 mL of normal human oral saliva sample and add it to 9 mL of sterile water, shake it thoroughly and dilute it; From the dilution of 10 -7 Take 100 μL of the sample suspension and spread it on MRS solid medium, and incubate it upside down in an anaerobic incubator at 37°C for 48 h; After a single colony grows on the plate, pick the single colony for purification. Repeat this process three or more times until a pure colony is cultured.

2. The use of a strain of Lactobacillus plantarum for preventing Streptococcus mutans infection according to claim 1, characterized in that: The experimental method for the microbiological characteristics of Lactobacillus plantarum W94 comprises the following steps: Lactobacillus plantarum W94 was inoculated on MRS solid medium, and the colony morphology, color and transparency were observed; The staining characteristics of the bacteria were observed by Gram staining; The growth characteristics of the bacteria were measured at a constant temperature of 37°C or under anaerobic conditions; The lactic acid bacteria biochemical identification tube was used to identify the response of Lactobacillus plantarum W94 to 11 carbohydrates.

3. The use of a strain of Lactobacillus plantarum for preventing Streptococcus mutans infection according to claim 2, characterized in that: The lactic acid bacteria biochemical identification tube was used to conduct carbohydrate fermentation test on Lactobacillus plantarum W94, and 11 carbohydrates including esculin and cellobiose were selected as reaction substrates.

4. The use of a strain of Lactobacillus plantarum for preventing Streptococcus mutans infection according to claim 3, characterized in that: The preparation method of the aseptic supernatant of Lactobacillus plantarum W94 comprises the following steps: The revived Lactobacillus plantarum W94 was inoculated into MRS liquid medium and cultured anaerobically at 37°C for 48 h; The fermentation supernatant was collected, centrifuged at 12000g for 10 minutes, filtered twice with a 0.22 μm filter membrane to obtain a sterile supernatant (CFS), and placed in a 4°C refrigerator for use.

5. The use of a strain of Lactobacillus plantarum for preventing Streptococcus mutans infection according to claim 4, characterized in that: The experimental method for the effect of the sterile supernatant of Lactobacillus plantarum W94 on the growth of Streptococcus mutans comprises the following steps: After taking out mutans Streptococcus UA159 from the -80℃ freezer and thawing, 100 μL was spread on TSA plates. After activation and passage three times, a single colony was picked and inoculated into TSB broth and cultured until OD600 reached 0.

6. Add 200 μL of mutans Streptococcus in the logarithmic growth phase to 10 mL of TSB semi-solid medium, mix well and pour on a TSA solid plate to form a double-layer agarose plate; Use a 7-mm diameter hole puncher to punch holes in the double-layer agarose plate, and add 100 μL of CFS or MRS liquid culture medium to each well as a negative control; After culturing in an anaerobic chamber at 37°C for 24 hours, the samples were diluted and spread in multiple proportions, the number of viable bacteria was calculated, and a growth curve was drawn.

6. The use of a strain of Lactobacillus plantarum for preventing Streptococcus mutans infection according to claim 5, characterized in that: The experimental method for the effect of sterile supernatant of Lactobacillus plantarum W94 on biofilm formation of Streptococcus mutans comprises the following steps: CFS and Streptococcus mutans cultured to the logarithmic phase were mixed in a 1:1 ratio and added to a 96-well plate, 200 μL was added to each well, and 5 groups were repeated, with 5 parallel controls in each group; After culturing in an anaerobic box at 37°C for 24 h, the culture medium in the wells was discarded and PBS was added for washing three times; Add 200 μL of 95% methanol to each well for 15 minutes, then discard the methanol and dry naturally at room temperature; Add 200 μL of 1% crystal violet to each well for staining for 10 minutes, then rinse with PBS to remove excess dye and dry naturally at room temperature; 160 μL of 33% glacial acetic acid was added to each well to dissolve the dye adhering to the bacteria, and 125 μL of the soluble dye was transferred from each well to a new 96-well plate, and the absorbance was measured at a wavelength of 630 nm.

7. The use of a strain of Lactobacillus plantarum for preventing Streptococcus mutans infection according to claim 6, characterized in that: Lactobacillus plantarum W94 can utilize and decompose esculin, cellobiose, maltose, sucrose, sorbitol, inulin, raffinose, lactose, mannitol, salicin and sodium hippurate.

8. The use of a strain of Lactobacillus plantarum for preventing Streptococcus mutans infection according to claim 7, characterized in that: The aseptic fermentation supernatant of Lactobacillus plantarum W94 has an inhibitory effect on Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa, and has a broad-spectrum antibacterial effect.

9. The use of a strain of Lactobacillus plantarum for preventing Streptococcus mutans infection according to claim 8, characterized in that: CFS at 8% dilution could inhibit the growth of Streptococcus mutans.

10. A strain of Lactobacillus plantarum, characterized in that Its taxonomic name is (Lactiplantibacillusplantarum) W94, which was deposited in the China Center for Type Culture Collection (CCTCC) on December 4, 2024, with a deposit number of CCTCCNO: M20242717, and the content of Lactobacillus plantarum is not less than 5.0×10 8 cfu / mL or 5.0×10 8 cfu / g.

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