Lactobacillus gasseri fmta1121e with the function of adjusting the vaginal micro-ecological environment and application thereof

Abstract

The present application relates to a kind of Lactobacillus gasseri FMTA1121E with the function of adjusting vaginal microecological environment and its application, the classification of the Lactobacillus gasseri FMTA1121E is named Lactobacillus gasseri, the preservation number is CGMCC No.34962, the bacteria can metabolize and produce lactic acid, gamma-aminobutyric acid and hydrogen peroxide and other beneficial ingredients, to adjust the environment of reproductive tract, improve health degree;And for escherichia coli, staphylococcus aureus, gardnerella vaginalis, candida albicans, neisseria gonorrhoeae and other common vaginal pathogenic bacteria have better bacteriostatic and bactericidal effect.Therefore, the Lactobacillus gasseri FMTA1121E strain can be applied to the preparation of preparation for preventing and treating vaginitis and other related reproductive tract diseases.

Description

Technical Field

[0001] This invention belongs to the field of microbial culture technology and relates to a Lactobacillus gasseri FMTA1121E that has the function of regulating the vaginal microecological environment and its application. Background Technology

[0002] The human body's surface and cavities that connect to the outside world are inhabited by microorganisms that have no harmful effects on the body, collectively known as the normal microbiota or normal flora. These are beneficial and essential to the human body. Through long-term evolution, adaptation, and natural selection, different species within the normal flora, the normal flora and the host, and the normal flora, host, and environment maintain a dynamic balance, forming an interdependent and mutually restrictive system. The female lower genital tract is an open cavity and an important microecological region within the human body, normally composed of a microecological system dominated by lactobacilli and other beneficial bacteria. The vaginal microecology is a highly sensitive system, easily affected by endogenous and exogenous factors, leading to the development of diseases.

[0003] The vaginal flora of a healthy woman consists of various anaerobic and aerobic bacteria. The microbiota colonizing a normal vagina mainly comprises bacteria, fungi, protozoa, and viruses. They primarily inhabit the folds of the vaginal mucosa, followed by the fornix, and some are found in the cervix. Bacteria mainly include Gram-positive aerobic and facultative anaerobic bacteria, as well as Gram-negative aerobic and facultative anaerobic bacteria. Under normal conditions, the anaerobic and aerobic bacteria in the vagina are in a dynamic balance. In addition, there are some pathogens, such as Campylobacter molluscum, Mycoplasma, and Candida.

[0004] In normal vaginal flora, lactobacilli are dominant. Lactobacilli, normally present in the vagina, play a crucial role in maintaining the normal vaginal flora. They can act on glycogen within vaginal squamous epithelial cells, breaking it down into lactic acid, creating a slightly acidic environment in the vagina that is unfavorable to the excessive growth of other parasitic bacteria. Furthermore, lactobacilli can prevent pathogenic microorganisms from adhering to vaginal epithelial cells through substitution and competitive exclusion mechanisms. Simultaneously, they secrete hydrogen peroxide, bacteriocins, bacterioids, and biosurfactants to inhibit the growth of pathogenic microorganisms, thereby maintaining the balance of the vaginal microecological environment. However, existing probiotic products applied to the regulation of the vaginal microecological environment suffer from drawbacks such as weak strain colonization and poor efficacy. Therefore, developing a probiotic agent that can effectively improve vaginal health and regulate the female reproductive tract microecological environment has significant application value. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a Lactobacillus gasseri FMTA1121E that has the function of regulating the vaginal microecological environment and its application.

[0006] To achieve this objective, the present invention adopts the following technical solution: In a first aspect, the present invention provides a *Lactobacillus gasseri* FMTA1121E that has the function of regulating the vaginal microecological environment, wherein the *Lactobacillus gasseri* FMTA1121E is classified as *Lactobacillus gasseri*. Lactobacillus gasseri The accession number is CGMCC No. 34962, and the accession date is June 23, 2025.

[0007] This invention isolates and preserves a novel *Lactobacillus gasseri* strain that can regulate the vaginal microecological environment from the secretions of healthy female reproductive tracts, naming it *Lactobacillus gasseri* FMTA1121E. This bacterium can metabolize and produce beneficial components such as lactic acid, γ-aminobutyric acid (GABA), and hydrogen peroxide to regulate the reproductive tract environment and improve health. It also exhibits good antibacterial and bactericidal effects against common vaginal pathogens such as *Escherichia coli*, *Staphylococcus aureus*, *Gardnerella vaginalis*, *Candida albicans*, and *Neisseria gonorrhoeae*. Therefore, this *Lactobacillus gasseri* FMTA1121E strain can be used to prepare preparations for the prevention and treatment of vaginitis and other related reproductive tract diseases.

[0008] In a second aspect, the present invention provides a culture of Lactobacillus gasseri FMTA1121E as described in the first aspect, the culture being prepared by inoculating Lactobacillus gasseri FMTA1121E into a culture medium and culturing it at 35-38°C for 20-48 h.

[0009] The "35-38℃" mentioned above can be, for example, 35℃, 35.5℃, 36℃, 36.5℃, 37℃, 37.5℃, 38℃, etc. Other specific point values ​​within this range can be selected, which will not be elaborated here.

[0010] The "20-48 h" mentioned above can be, for example, 20 h, 22 h, 25 h, 28 h, 30 h, 32 h, 35 h, 40 h, 45 h, 48 h, etc. Other specific point values ​​within this range can be selected, which will not be elaborated here.

[0011] Thirdly, the present invention provides a probiotic agent that has the function of regulating the vaginal microecological environment, wherein the strain in the probiotic agent that has the function of regulating the vaginal microecological environment includes the Lactobacillus gasseri FMTA1121E strain as described in the first aspect.

[0012] Preferably, in the probiotic agent, the viable count of Lactobacillus gasseri FMTA1121E is not less than 1×10⁻⁶. 8 CFU / mL or 1×10 8 CFU / g, for example 1×10 8 CFU / mL (CFU / g), 2×108 CFU / mL (CFU / g), 5×10 8 CFU / mL (CFU / g), 8×10 8 CFU / mL (CFU / g), 1×10 9 CFU / mL (CFU / g), 5×10 9 CFU / mL (CFU / g), 1×10 10 CFU / mL (CFU / g), etc. Other specific point values ​​within this range can be selected, which will not be elaborated here.

[0013] Preferably, the probiotic strains in the probiotic agent also include *Lactobacillus fermentum*. Limosilactobacillus leaven FMTA1113G strain, with accession number CGMCC No. 35371, was accessed on July 25, 2025.

[0014] This invention also creatively discovered the above-mentioned fermenting *Lactobacillus mucinus*. Limosilactobacillus fermentum FMTA1113G strain can interact with Lactobacillus gasseri. Lactobacillus gasseri The combination of FMTA1121E strain and FMTA1113G strain showed superior effects in improving the vaginal microecological environment and alleviating inflammatory symptoms compared to single bacterial agents or other combination methods. This indicates that FMTA1121E strain and FMTA1113G strain have a synergistic effect in regulating the vaginal microecological environment, preventing and controlling vaginal pathogens, and improving reproductive tract health.

[0015] Preferably, the ratio of viable counts of *Lactobacillus gasseri* FMTA1121E to *Lactobacillus fermentum* FMTA1113G is 1:10-10:1, for example, it can be 1:10, 1:9, 1:8, 1:7, 1:6, 1:5, 1:4, 1:3, 1:2, 1:1, 2:1, 3:1, 5:1, 6:1, 8:1, 10:1, etc. Other specific values ​​within this range can be selected, and will not be elaborated here.

[0016] Preferably, the dosage form of the probiotic agent includes solution, lyophilized powder, capsule, gel, suppository, tablet or granule.

[0017] Preferably, the probiotic agent further includes a protectant.

[0018] Preferably, the protective agent comprises any one or a combination of at least two of the following: skim milk, gelatin, dextrin, gum arabic, dextran, sodium alginate, polyvinylpyrrolidone, sucrose, lactose, trehalose, sorbitol, or xylitol.

[0019] Fourthly, the present invention provides the use of Lactobacillus gasseri FMTA1121E as described in the first aspect, or the culture as described in the second aspect, or the probiotic agent as described in the third aspect, in the preparation of a formulation for preventing and treating vaginal pathogens.

[0020] Compared with the prior art, the present invention has the following beneficial effects: This invention isolates and preserves a novel *Lactobacillus gasseri* strain that can improve female reproductive tract health from the secretions of healthy women's reproductive tracts, naming it *Lactobacillus gasseri* FMTA1121E. This bacterium can metabolize and produce beneficial components such as lactic acid, γ-aminobutyric acid (GABA), and hydrogen peroxide to regulate the reproductive tract environment and improve health. It also exhibits good antibacterial and bactericidal effects against common vaginal pathogens such as *Escherichia coli*, *Staphylococcus aureus*, *Gardnerella vaginalis*, *Candida albicans*, and *Neisseria gonorrhoeae*. Therefore, this *Lactobacillus gasseri* FMTA1121E strain can be used to prepare preparations for the prevention and treatment of vaginitis and other related reproductive tract diseases.

[0021] The FMTA1121E strain involved in this invention is classified as Lactobacillus gasseri. Lactobacillus gas station The depositary institution is the China General Microbiological Culture Collection Center (CGMCC), with accession number CGMCC No. 34962, deposit date June 23, 2025, and deposit address No. 3, No. 1 Beichen West Road, Chaoyang District, Beijing.

[0022] The FMTA1113G strain involved in this invention is classified as *Lactobacillus fermentatus*. Limosilactobacillus fermentum The depositary institution is the China General Microbiological Culture Collection Center (CGMCC), with accession number CGMCC No. 35371, deposit date July 25, 2025, and deposit address No. 3, No. 1 Beichen West Road, Chaoyang District, Beijing. Attached Figure Description

[0023] Figure 1 This is a microscopic image of the Gram staining results of Lactobacillus gasseri FMTA1121E; Figure 2 The image shows the hemolytic test results of Lactobacillus gasseri FMTA1121E and Lactobacillus fermentum FMTA1113G. Figure 3 This is a graph showing the results of the drug resistance test for Lactobacillus gasseri FMTA1121E; Figure 4 This is a graph showing the results of the antibacterial ability test of Lactobacillus gasseri FMTA1121E and Lactobacillus fermentum FMTA1113G. Detailed Implementation

[0024] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention.

[0025] The following information pertains to the bacterial species: ① The strain FMTA1121E is classified as Lactobacillus gasseri. Lactobacillus gasseri The accession number is CGMCC No. 34962; ② The strain FMTA1113G is classified as *Lactobacillus fermentatus*. Limosilactobacillus leaven The accession number is CGMCC No. 35371; ③ The ATCC 33323 strain mentioned below is Lactobacillus gasseri ATCC 33323 strain.

[0026] The source information for the materials mentioned below is as follows: MRS solid medium (HB0384-5), MRS liquid medium (HB0384-1), BHI liquid medium (HB8297-5), YPD liquid medium (HB5193-1), and Columbia medium (HB8511) were all purchased from Qingdao Haibo Biotechnology Co., Ltd.

[0027] Hydrogen peroxide detection kit (Nanjing Jiancheng Bioengineering Institute, A064-1-1), D-lactic acid detection kit (Nanjing Jiancheng Bioengineering Institute, A019-2-1), L-lactic acid detection kit (Nanjing Jiancheng Bioengineering Institute, A019-3-1), Gram staining kit (Adamas Life, C8074-1), γ-aminobutyric acid (GABA) content detection kit (Beijing Box Biotechnology Co., Ltd., AKAM023M), bacterial genomic DNA extraction kit (Omega, D3350-02).

[0028] The following methods for preparing bacterial suspensions and bacterial powders are as follows: After activating the bacterial strains, they are inoculated into culture media for cultivation to obtain culture solutions; the culture solutions are centrifuged, and the bacterial suspensions are resuspended to obtain bacterial suspensions, or a protective agent is added for freeze-drying to obtain freeze-dried bacterial powder products.

[0029] Example 1 In this embodiment, a strain of Lactobacillus gasseri capable of regulating the vaginal microecological environment was isolated and screened. The steps are as follows: Secretions were collected from healthy women, serially diluted with PBS, and plated onto MRS solid medium. The plates were then anaerobically incubated at 37°C for 48 h. Single colonies of different sizes, colors, and morphologies were picked and streaked onto MRS solid medium for purification, ultimately yielding single colonies of uniform size, color, and morphology. These single colonies were then transferred to MRS liquid medium and anaerobically incubated at 37°C for 48 h. Finally, they were preserved using 30% glycerol and stored at -80°C.

[0030] Example 2 This embodiment performs morphological identification and 16S rRNA molecular biological identification on the strains screened in Example 1. The steps are as follows: (1) After anaerobic culture of the strains screened in Example 1 at 37°C for 48 h, 5 μL of bacterial solution was evenly spread on a glass slide, Gram staining was performed using a Gram staining kit, and the results were observed under an oil immersion microscope. The results showed that *Lactobacillus gasseri* FMTA1121E strain, after Gram staining, was Gram-positive and rod-shaped. Figure 1 Its colony morphology on MRS solid medium is milky white, with clear edges, smooth surface, round shape, and slight convexity.

[0031] (2) The strain was inoculated at a ratio of 2% (v / v) into centrifuge tubes containing 20 mL of MRS liquid medium and cultured at 37°C for 24 h. After centrifugation at 8000 rpm for 10 min, the supernatant was discarded, and the bacterial cells were collected. The genome of the strain was extracted, and PCR amplification was performed using universal bacterial primers. The amplification product was sent to a sequencing company for sequencing identification. Sequencing analysis revealed that the 16S rRNA sequence of this strain is shown in SEQ ID No:1. The sequence obtained was compared with the nucleic acid sequence in GeneBank, and the results showed that the strain was *Lactobacillus gasseri*.

[0032] SEQ ID No:1:

[0033] Based on the results of 16S rRNA molecular biological identification and morphological identification in Example 2, the strain was confirmed to belong to Lactobacillus gasseri and named Lactobacillus gasseri. Lactobacillus gasseri FMTA1121E strain.

[0034] Test Example 1 Detection of the content level of bacterial metabolites (1) Hydrogen peroxide After two transfers and activation, Lactobacillus gasseri FMTA1121E bacterial culture was transferred to MRS liquid medium at an inoculum of 1% and cultured anaerobically at 37°C for 48 h. 1 mL of the culture was taken, centrifuged at 8000 rpm for 5 min, and the supernatant was collected. The hydrogen peroxide content produced by the strain was calculated according to the instructions of the hydrogen peroxide detection kit.

[0035] (2) D-lactic acid Take 5 µL of Lactobacillus gasseri FMTA1121E bacterial culture after anaerobic culture at 37℃ for 48 h, add it to 2.5 mL of sterile distilled water and mix well. Adjust the pH to 8 with 0.5 M KOH, mix well, let stand at 25℃ for 30 min, centrifuge at 12000 rpm for 10 min, take the supernatant, and perform the D-lactic acid detection according to the instructions of the D-lactic acid detection kit to calculate the D-lactic acid content produced by the strain.

[0036] (3) L-lactic acid After two inoculations, the activated Lactobacillus gasseri FMTA1121E culture was transferred to MRS liquid medium at an inoculation rate of 1% and cultured anaerobicly at 37°C for 48 h. 1 mL of the culture was centrifuged at 5000 rpm for 5 min, and the supernatant was diluted 20 times with PBS. The L-lactic acid content produced by the strain was calculated according to the instructions of the L-lactic acid assay kit.

[0037] (4) γ-aminobutyric acid After two transfers and activations, the FMTA1121E bacterial culture was transferred to MRS liquid medium at an inoculum rate of 1% and cultured anaerobically at 37°C for 48 h. 1 mL of the culture was taken, centrifuged at 8000 rpm for 10 min, and the supernatant was collected. The content of γ-aminobutyric acid (GABA) produced by the strain was calculated according to the instructions of the γ-aminobutyric acid (GABA) content detection kit.

[0038] The test results are shown in Table 1.

[0039] Table 1 Hydrogen peroxide decomposition produces hydroxyl radicals and superoxide anions, which have strong oxidizing properties. These can disrupt the lipid bilayer structure of pathogen cell membranes, leading to leakage of cell contents. It significantly inhibits both aerobic and anaerobic bacteria, including Gardnerella vaginalis, Escherichia coli, and Staphylococcus aureus. Simultaneously, it inhibits the motility and metabolic activity of Trichomonas vaginalis, creating a favorable environment for lactobacillus colonization. Furthermore, hydrogen peroxide can regulate vaginal mucosal immunity through oxidative stress, reducing the excessive release of inflammatory factors.

[0040] D-lactic acid can effectively maintain the acidic environment of the vagina and prevent external pathogens (such as bacteria and viruses) from invading the vaginal epithelium. This mechanism plays an important role in maintaining the integrity of the vaginal mucosal barrier.

[0041] L-lactic acid can rapidly lower vaginal pH to 3.8-4.5, with high dissociation and sustained acidity. It also disrupts the permeability of pathogenic bacterial cell membranes, inhibits nucleic acid synthesis, and synergistically enhances the antibacterial effect with hydrogen peroxide. Furthermore, it promotes vaginal epithelial cell proliferation and repair, strengthening the mucosal barrier function.

[0042] GABA can serve as a metabolic substrate for certain lactobacilli, enhancing strain activity by regulating their glycolysis pathways, thereby maintaining the colonization dominance of the vaginal flora and resisting the adhesion of pathogenic bacteria. GABA, in synergy with lactic acid, hydrogen peroxide, and other substances, maintains the vaginal pH at a slightly acidic level (3.8–4.5), inhibiting the growth of pathogenic pathogens (such as Trichomonas vaginalis and Candida albicans) with relatively high optimal pH levels; it also inhibits the biosynthesis of pathogenic bacteria (such as Staphylococcus aureus) by interfering with their amino acid metabolic pathways. Furthermore, its own dissociation properties can buffer local pH fluctuations, enhancing the stability of the microenvironment.

[0043] According to the statistics in the table, Lactobacillus gasseri FMTA1121E has the ability to produce hydrogen peroxide, lactic acid and γ-aminobutyric acid, which can regulate the vaginal environment in multiple ways, improve the health of the reproductive tract, reduce the growth and infection of pathogens, and inhibit the occurrence of related reproductive tract diseases.

[0044] Test Example 2 Hemolytic test Activated beta-hemolytic streptococci (control), Lactobacillus gasseri FMTA1121E, and Lactobacillus fermentum FMTA1113G were streaked onto Columbia blood agar (5% defibrinated sheep blood). After anaerobic incubation at 37°C for 24 h, the hemolytic activity of each colony was observed. The results are as follows: Figure 2 As shown.

[0045] Hemolysis is one of the core indicators for assessing microbial safety. Bacteria destroy red blood cell membranes by producing hemolysin, releasing hemoglobin and forming characteristic hemolytic zones on blood agar plates. The results in the figure show that beta-hemolytic streptococci showed transparent hemolytic zones around their colonies after culturing on Columbia blood agar plates; however, no hemolytic zones were observed around the colonies of *Lactobacillus gasseri* FMTA1121E and *Myxobacterium fermentum* FMTA1113G, indicating that these two strains are non-hemolytic and will not cause significant hemolytic harm.

[0046] Test Example 3 Drug resistance test Lactobacillus gasseri FMTA1121E and Lactobacillus fermentum FMTA1113G were activated twice by transfer, and then transferred to MRS liquid medium at an inoculum of 1% each, and cultured anaerobically at 37°C for 48 h. The cultured bacterial solution was then diluted 5-fold with PBS (OD200). 600 (For a concentration of 0.1), 100 μL of bacterial suspension dilution was spread onto an MRS agar plate and dried at 25℃ for 4 min. Antimicrobial susceptibility test discs (ampicillin, ceftriaxone, cefotaxime, tetracycline, erythromycin, penicillin, vancomycin, chloramphenicol) were evenly placed on the agar plate surface, gently pressed with tweezers, and incubated upside down at 37℃ for 24 h. The diameter of the inhibition zone was measured and recorded. Three replicates were set up for each group. The test results are shown in Table 2 and [Table data missing]. Figure 3 As shown in (FMTA1121E).

[0047] Table 2 According to relevant test statistics, Lactobacillus gasseri FMTA1121E is sensitive to all eight antibiotics. Figure 3 ); Lactobacillus fermentum FMTA1113G showed sensitivity to seven antibiotics except vancomycin (naturally resistant), and did not develop resistance.

[0048] Test Example 4 Antibacterial ability test (1) After activating strains FMTA1121E, FMTA1113G and ATCC 33323, they were inoculated into culture medium and cultured to obtain culture solution; the culture solution was centrifuged and the bacterial suspension was resuspended for later use.

[0049] Groups: S1 (FMTA1121E bacterial suspension), S2 (FMTA1113G bacterial suspension), S3 (FMTA1121E bacterial suspension + FMTA1113G bacterial suspension, viable cell ratio 10:1), S4 (FMTA1121E bacterial suspension + FMTA1113G bacterial suspension, viable cell ratio 1:1), S5 (FMTA1121E bacterial suspension + FMTA1113G bacterial suspension, viable cell ratio 1:10), S6 (ATCC 33323 bacterial suspension + FMTA1113G bacterial suspension, viable cell ratio 10:1), with a total viable cell count of 1×10⁻⁶ in each group. 8 CFU / mL.

[0050] (2) Preparation of indicator bacterial suspension: Staphylococcus aureus, Escherichia coli, Candida albicans, Gardnerella vaginalis and Neisseria gonorrhoeae pathogens were cultured in BHI medium, BHI medium, YPD medium, Columbia medium and Columbia medium respectively, and shaken at 200 rpm and 37℃ for 18 h. The bacterial concentration was then adjusted to 10. 6 CFU / mL available for use.

[0051] (3) The antibacterial activity of *Lactobacillus gasseri* FMTA1121E and *Lactobacillus fermentum* FMTA1113G was determined using the Oxford cup method. 200 μL of a 10... 6 CFU / mL indicator bacterial suspensions were spread on the surface of solid culture media. After placing the media in Oxford cups, 100 μL of *Lactobacillus gasseri* FMTA1121E and *Lactobacillus fermentum* FMTA1113G bacterial suspensions were added separately to each cup, and the cultures were incubated at 37℃ for 24 h. Three replicates were performed for each condition, and the diameter of the inhibition zone was measured using calipers, and the average value was calculated. The results are shown in Table 3. The inhibition zone results for strains FMTA1121E and FMTA1113G are shown in Table 3. Figure 4 As shown.

[0052] Table 3 The test results show that the *Lactobacillus gasseri* FMTA1121E strain provided by this invention has a broad-spectrum antibacterial effect against common vaginal pathogens, effectively inhibiting the growth and infection of related pathogens, reducing their damage and destruction to the reproductive tract, and effectively maintaining the health of the reproductive tract. Furthermore, it was found that when *Lactobacillus fermentum* FMTA1113G and *Lactobacillus gasseri* FMTA1121E are used in combination, the resulting compound bacterial agent exhibits even better antibacterial effects.

[0053] Test Example 5 a. Test of the ability to intervene in the morphological transformation of Candida albicans (1) Take 1 mL of Lactobacillus gasseri FMTA1121E culture after two transfections and activations, centrifuge at 8000 rpm for 10 min, collect the supernatant and set aside; Take 10 mL of Candida albicans culture after two consecutive passages, centrifuge at 8000 rpm for 10 min, remove the supernatant, add 10 mL of PBS to resuspend and mix, centrifuge again to remove the supernatant, add 10 mL of YPD culture medium to resuspend, and obtain Candida albicans culture for later use.

[0054] (2) Grouping: negative control group (1 mL Candida albicans culture + 1 mL MRS medium); positive control group (1 mL Candida albicans culture + 1 mL MRS medium containing streptomycin sulfate); experimental group (1 mL Candida albicans culture + 1 mL Lactobacillus gasseri culture supernatant + streptomycin sulfate). The total volume of each group was 2 mL. The final concentration of streptomycin sulfate in the system in the positive control group and the experimental group was 1%. Each group was replicated twice. After anaerobic culture at 37℃ for 2 h, samples were taken for microscopic examination. The number of hyphae and yeast phases in the field of view was counted and the proportion of hyphae was calculated. The results are shown in Table 4.

[0055] Table 4 Candida albicans can switch between yeast and hyphal forms within the host. The hyphae enhance adhesion to vaginal epithelial cells through adhesins and penetrate the mucosal layer, causing vaginal inflammation. The data in the table show that Lactobacillus gasseri FMTA1121E significantly interferes with the hyphal conversion ability of Candida albicans. This strain effectively prevents vaginal infections and maintains reproductive tract health by reducing the number of hyphae. Inhibiting the morphological transformation of Candida albicans can be used as an adjunct treatment for vulvovaginal candidiasis. It can also be used in combination with low-dose antifungal drugs to reduce the development of drug resistance in pathogens.

[0056] b. Test on the ability to inhibit Candida albicans biofilm growth (1) The preparation of Lactobacillus gasseri supernatant and Candida albicans culture is based on step a.

[0057] (2) Grouping: negative control group (100 µL Candida albicans culture + 100 µL MRS medium); experimental group (100 µL Candida albicans culture + 100 µL Lactobacillus gasseri culture supernatant).

[0058] (3) The mixed systems from the negative control group and the experimental group were transferred to 96-well plates, with three replicates for each group. After incubation at 37°C for 24 h, the liquid in the wells was removed, and the plates were washed twice with 200 μL of PBS and dried. Then, 200 μL of 0.1% crystal violet was added for staining for 15 min, followed by washing three times with PBS and drying. After decolorization with 200 μL of anhydrous ethanol for 15 min, the OD was measured. 570nm The value was calculated, and the inhibition rate of Lactobacillus gasseri against Candida albicans biofilm was calculated according to the following formula.

[0059] ; Among them, ODc is the negative control group OD 570nm Value; ODt is the OD of the experimental group. 570nm value.

[0060] Biofilms are composed of microbial communities and their encapsulating extracellular polymers and matrix networks. They are closely related to the formation of antimicrobial resistance, gene transfer, and persistent infection, and can enhance tolerance to antimicrobial substances (such as H2O2, lactic acid, and bacteriocins). Healthy women have thin and loose vaginal biofilms, while women with vaginitis often have thick biofilms, making treatment more difficult. During routine antibiotic treatment for vaginitis, patients may experience short-term clinical symptom relief, but after discontinuation of medication, dense and active biofilms rapidly appear on the vaginal mucosa, which is one of the important reasons for persistent infection or recurrence of vaginitis.

[0061] According to the test calculation results, the Lactobacillus gasseri FMTA1121E provided by this invention can achieve an inhibition rate of 56.91% against Candida albicans biofilm in 24 hours, effectively inhibiting the growth and reproduction of Candida albicans in vaginal tissue, indicating that Lactobacillus gasseri FMTA1121E has a good inhibitory effect on Candida albicans biofilm.

[0062] The applicant declares that the technical solution of this invention is illustrated by the above embodiments, but this invention is not limited to the above embodiments, that is, it does not mean that this invention must rely on the above embodiments to be implemented. Those skilled in the art should understand that any improvements to this invention, equivalent substitutions of raw materials for the products of this invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of this invention.

[0063] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0064] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

Claims

1. A probiotic agent with the function of regulating the vaginal microecological environment, characterized in that, The probiotic strains in the probiotic agent consist of Lactobacillus gasseri FMTA1121E and Lactobacillus fermentum FMTA1113G with a live count ratio of 1:10-10:

1. The Lactobacillus gasseri FMTA1121E is classified as Lactobacillus gasseri ( Lactobacillus gasseri The accession number is CGMCC No. 34962, and the accession date is June 23, 2025. The fermenting *Lactobacillus fermentatus* FMTA1113G is classified as *Lactobacillus fermentatus* (… Limosilactobacillus fermentum The accession number is CGMCC No. 35371, and the accession date is July 25, 2025.

2. The probiotic agent as described in claim 1, characterized in that, In the probiotic preparation, the viable count of Lactobacillus gasseri FMTA1121E is not less than 1×10⁻⁶. 8 CFU / mL or 1×10 8 CFU / g.

3. The probiotic agent as described in claim 2, characterized in that, The dosage forms of the probiotic agent include solutions, lyophilized powders, capsules, gels, suppositories, tablets, or granules.

4. The probiotic agent as described in claim 1, characterized in that, The probiotic agent also includes a protectant.

5. The probiotic agent as described in claim 4, characterized in that, The protective agent includes any one or a combination of at least two of the following: skim milk, gelatin, dextrin, gum arabic, dextran, sodium alginate, polyvinylpyrrolidone, sucrose, lactose, trehalose, sorbitol, or xylitol.

6. The use of a probiotic agent as described in any one of claims 1-5 in the preparation of a formulation for preventing and treating vaginal pathogens; The vaginal pathogens are any one or a combination of at least two of Staphylococcus aureus, Escherichia coli, Candida albicans, Gardnerella vaginalis, or Neisseria gonorrhoeae.

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