Desert cat-derived roitt's myxobacterium gambol-lr1 and application thereof

Abstract

The application discloses a strain of desert cat-derived Royte's mucus lactobacillus Gambol-LR1 and an application thereof, and belongs to the technical field of pet probiotics. In view of the poor host adaptability of the existing commercial Royte's mucus lactobacillus, the weak tolerance of the cat digestive tract to extreme environment, the low in-vivo Royte's lactobacillus in-situ production efficiency, and the limited bacteriostatic effect, the application is isolated from the feces of healthy desert cats, and the preservation number is CGMCC No. 37228. The 16S rDNA sequence is shown as SEQ ID NO: 1. The strain has excellent acid and bile salt tolerance, can be stably planted in the cat digestive tract, has a broad-spectrum bacteriostatic effect on the pathogenic bacteria of the cat's high-incidence intestinal tract, oral cavity and urinary tract. The strain has no hemolysis risk, is suitable for various antibiotic medication scenarios, has high biological safety, and can produce Royte's lactobacillus by glycerol and vitamin B 12 synergistically enhance the bacteriostatic capacity. The strain is accurately adapted to the intestinal microecology of cats, and can be used for preparing cat food, health products and anti-infection drugs, and preventing and treating cat periodontal disease, bacterial enteritis, urinary tract infection and other diseases, and has a wide industrial application prospect.

Description

Technical Field

[0001] This invention belongs to the field of pet probiotic microbial technology and pet health product technology, specifically involving a strain of desert cat-derived Lactobacillus reuteri Gambol-LR1 and its application in pet food, health products and anti-infective drugs. Background Technology

[0002] With the increasing popularity of pet ownership, the demand for refined and healthy pet care continues to grow. Regulating the gut microbiota and preventing bacterial diseases in cats have become core pain points in the pet health field. Probiotics, as a core ingredient for regulating pet gut microbiota, enhancing immunity, and preventing bacterial infections, are widely used in pet food and health products.

[0003] Lactobacillus reuteri is a high-quality probiotic that specifically produces reuterin, a broad-spectrum antibacterial substance, possessing beneficial functions such as regulating intestinal flora, inhibiting pathogens, and anti-inflammatory and gut-protective effects. However, currently commercially available Lactobacillus reuteri strains are mostly isolated from hosts such as humans, pigs, and poultry, exhibiting severe limitations in host adaptability. Cats are obligate carnivores with a stomach pH that can be as low as 2.0. Their digestive tract is an extreme environment of high body temperature, strong acidity, and high bile salts. Common exogenous strains have extremely poor tolerance to this environment, resulting in low survival rates of live bacteria after oral administration and difficulty in colonizing the cat's intestines, easily leading to the problem of "bacteria passing through without leaving a trace."

[0004] Meanwhile, existing commercial probiotic strains have significant technical shortcomings: First, in the low-glycerol, low-coenzyme environment of the cat's gut, the in situ production of reuterin is extremely inefficient, failing to achieve effective antibacterial activity. Second, the industry mostly uses in vitro purified reuterin as a chemical additive, which cannot achieve continuous colonization and protection of live bacteria, resulting in poor maintenance effects and limitations in additive use. Third, current probiotics lack antibacterial data targeting common oral and urinary tract pathogens in cats, exhibiting poor targeting and insufficient precision in conditioning, making it difficult to meet the specific health maintenance needs of cats. Therefore, developing a feline probiotic with strong host adaptability, excellent stress resistance, efficient in vivo production of reuterin, and targeted inhibition of specific feline pathogens is key to overcoming the industry's technical bottlenecks. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies by providing a strain of Lactobacillus reuteri Gambol-LR1 from the desert cat, which is adapted to the physiological characteristics of cats, has strong stress resistance, and excellent antibacterial properties. At the same time, it provides its bacterial agent and its application in cat health products, solving the industry pain points of poor host adaptability, weak colonization ability, poor in vivo antibacterial effect, and insufficient targeting of existing probiotics.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: This invention first provides a strain of *Limosilactobacillus reuteri* Gambol-LR1 derived from the desert cat. This strain was isolated from a fecal sample of a healthy desert cat and identified as *Limosilactobacillus reuteri* by 16S rDNA sequencing and alignment, and named Gambol-LR1. This strain has been deposited at the China General Microbiological Culture Collection Center (CGMCC) with accession number CGMCC No. 37228, deposited on December 29, 2025, at the Institute of Microbiology, Chinese Academy of Sciences, No. 3, Beichen West Road, Chaoyang District, Beijing. The 16S rDNA sequence of the strain is shown in SEQ ID NO:1.

[0007] Furthermore, the strain of this invention exhibits excellent tolerance to extreme environments and is adapted to the physiological characteristics of the feline digestive tract: After 3 hours of stress culture at 38.5℃ and pH=2, the survival rate reaches 444.1%; after 3 hours of stress culture at 38.5℃ and pH=3, the survival rate reaches 422%; after 3 hours of stress culture at 38.5℃ and 0.1% bile salts, the survival rate is 26.2%; and after 3 hours of stress culture at 38.5℃ and 0.2% bile salts, the survival rate is 53.2%. It can successfully withstand the highly acidic environment of the feline stomach and stably colonize the intestines.

[0008] Furthermore, the strain of this invention possesses broad-spectrum and highly effective antibacterial activity, showing significant inhibitory effects against both Gram-positive and Gram-negative pathogens commonly found in cats, including *Escherichia coli*, *Staphylococcus aureus*, *Salmonella*, *Porphyromonas gingivalis*, *Shigella flexneri* (from cats with cystitis), and *Shigella flexneri* (from cats with cystitis). This allows for targeted prevention and control of common feline diseases such as enteritis, periodontitis, and urinary tract infections. Specifically, the inhibition zone diameter against *Staphylococcus aureus* is 24.6 mm, against *Escherichia coli* is 27.4 mm, against *Porphyromonas gingivalis* is 11.4 mm, against *Shigella flexneri* (from cats with cystitis) is 20.1 mm, and against *Shigella flexneri* (from cats with cystitis) is 22.7 mm.

[0009] Furthermore, the strain of this invention has extremely high biosafety, no hemolytic activity, and will not cause damage to the cat's body; at the same time, it is sensitive to a variety of commonly used antibiotics such as chloramphenicol, carbenicillin, penicillin, cefazolin, piperacillin, ampicillin, ceftriaxone, cefuroxime, and ceftazidime, and can be adapted to clinical anti-infective combination drug scenarios in cats, with high drug safety.

[0010] Furthermore, the strain of the present invention possesses unique metabolic synergistic properties, and the strain can enhance the metabolism of glycerol and vitamin B. 12 Synergistic effect significantly enhances antibacterial ability; added glycerin and vitamin B 12After treatment, the diameter of the inhibition zone of the strain against Staphylococcus aureus, Escherichia coli, Porphyromonas gingivalis, Shigella flexneri from cats with cystitis, and Shigella flexneri from cats with cystitis increased by 43.09%, 47.81%, 46.49%, 39.80%, and 75.33%, respectively, solving the technical problem of insufficient in situ production of toxins and weak antibacterial effect of traditional strains.

[0011] The present invention also provides a probiotic preparation containing the desert cat-derived Lactobacillus reuteri Gambol-LR1, which contains at least one of the live bacteria of the strain and the strain's metabolites, and can be used as a core ingredient in various pet health products.

[0012] The present invention also provides a cat health product, including cat food, health products, and medicines, containing the strains or corresponding probiotic agents, which can regulate the cat's intestinal flora, enhance the body's immunity, and prevent and assist in the treatment of bacterial diseases.

[0013] This invention also provides the application of the desert cat-derived Lactobacillus reuteri Gambol-LR1, specifically for the preparation of health products that regulate the intestinal microecology of cats, prevent and treat periodontal disease, bacterial enteritis, and secondary urinary tract infections in cats, breaking through the technical limitations of traditional general-purpose probiotics and achieving precise health care for cats.

[0014] The present invention has the following beneficial effects: (1) Strong host adaptability: The strain of this invention is a probiotic homologous to desert cats. Compared with commercial strains from humans and livestock, it is fully adapted to the extreme physiological environment of the digestive tract of cats, which are obligate carnivores. It has excellent acid and bile salt resistance at cat body temperature and can stably colonize the cat's intestines, solving the core pain points of traditional strains such as low colonization rate and "no trace left after passing through".

[0015] (2) Targeted antibacterial performance is precise and efficient: The strain can specifically inhibit the oral, intestinal and urinary tract pathogens that are common in cats, filling the gap in the existing pet probiotics that lack antibacterial data on cat-specific pathogens. It can specifically prevent and treat diseases such as periodontal disease, bacterial enteritis and secondary urinary tract infections in cats.

[0016] (3) Significant in vivo synergistic effect: The strain of this invention can utilize trace amounts of glycerol and vitamin B in vivo. 12 It achieves a significant improvement in antibacterial efficacy, solving the problems of low in situ reuterin production and antibacterial failure in traditional strains. It eliminates the need for additional chemical antibacterial agents and enables long-lasting protection by live bacteria.

[0017] (4) Extremely high biosafety: The strain has no risk of hemolysis, no risk of drug resistance, is suitable for clinical drug use in pets, is safe and reliable to use, and meets the safety application standards for pet food, health products and medicines.

[0018] (5) Wide range of applications: The strains of this invention can be prepared into various probiotic agents, which can be widely used in cat staple food, supplementary food, health nutrition products and anti-infective adjuvant drugs to achieve intestinal microecological regulation and disease prevention throughout the cat's life cycle, with extremely high industrial value. Attached Figure Description

[0019] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0020] Figure 1 The image shows the survival rate results of the acid resistance test for the strain in Example 1.

[0021] Figure 2 The graph shows the survival rate of the strain in Example 1 in the bile salt tolerance test.

[0022] Figure 3 The image shows the results of the antibacterial ability test of the strain in Example 1.

[0023] Figure 4 This is a diagram showing the Circos diagram of the whole genome of strain Gambol-LR1 in Example 2.

[0024] Figure 5 The image shows the inhibition test results of strain Gambol-LR1 against Porphyromonas gingivalis in Example 3.

[0025] Figure 6 The image shows the antibacterial synergistic effect test results of strain Gambol-LR1 in Example 3.

[0026] Figure 7 The image shows the hemolytic test results of strain Gambol-LR1 in Example 4. Detailed Implementation

[0027] The following examples are provided to better understand the present invention, but do not limit the invention. Unless otherwise specified, the experimental methods in the following examples are conventional methods. Unless otherwise specified, the experimental materials used in the following examples were purchased from conventional biochemical reagent companies. All quantitative experiments in the following examples were performed in triplicate, and the results were averaged.

[0028] Example 1: Isolation and screening of Lactobacillus reuteri Gambol-LR1 strain from desert cats 1. Isolation of strains Fresh fecal samples from healthy desert cats were collected and inoculated into MRS broth medium. After enrichment culture in an anaerobic incubator at 37°C for 48 h, the samples were serially diluted with sterile PBS buffer and spread onto MRS solid medium containing 1% CaCO3, and cultured in an anaerobic incubator at 37°C for 48 h. Strains LR1, LR2, and LR3, which showed good growth, were selected from a large number of strains and enriched in MRS medium in an anaerobic incubator at 37°C for 24 h. The bacterial culture was then mixed with sterile 50% glycerol at a 1:1 ratio and stored at -80°C for later use.

[0029] 2. Screening of strains The glycerol-preserved bacterial strains LR1, LR2, and LR3 were aseptically inoculated into MRS broth medium and anaerobically cultured at 37°C for 24 hours, activating for three generations. After centrifugation, the bacterial culture was washed 2-3 times with sterile PBS. Acid resistance, bile salt resistance, and antibacterial activity tests were performed on the activated strains LR1, LR2, and LR3. The specific test procedures are as follows: (1) Acid resistance test The washed culture medium was resuspended in MRS broth medium with pH=2 and pH=3 and anaerobically cultured at 38.5℃. Samples were taken at 0h and 3h for serial dilution and spread on MRS solid medium plates. After anaerobic culture at 38.5℃ for 48h, the samples were counted.

[0030] Strain survival rate (%) = (T3 / T0) * 100% In the formula: T0 is the number of viable bacteria (cfu / mL) at 0h; T3 is the number of viable bacteria (cfu / mL) of the strain after 3h of acid resistance.

[0031] Experimental results are as follows Figure 1 As shown, strain LR1 had the best survival rate. At 38.5℃, the survival rate was 444.1% after 3 hours of survival at pH=2, and 422% after 3 hours of survival at pH=3.

[0032] (2) Bile salt tolerance test The washed culture medium was resuspended in MRS broth containing 0.2% and 0.1% bile salts, respectively, and cultured anaerobically at 38.5℃. Samples were taken at 0h and 3h for serial dilution and spread on MRS solid medium plates. After anaerobic culture at 38.5℃ for 48h, the samples were counted.

[0033] Strain survival rate (%) = (T3 / T0) * 100% In the formula: T0 is the number of viable bacteria (cfu / mL) at 0h; T3 is the number of viable bacteria (cfu / mL) after the strain has been salt-tolerant for 3h.

[0034] Experimental results are as follows Figure 2As shown, strain LR1 had the best survival rate. At 38.5℃, the survival rate was 26.2% after 3 hours under 0.1% bile salt conditions and 53.2% after 3 hours under 0.2% bile salt conditions.

[0035] (3) Determination of antibacterial ability Using Escherichia coli, Staphylococcus aureus, Porphyromonas gingivalis, Shigella freundii (from feces of cats with cystitis), and Shigella cystitis (from feces of cats with cystitis) as indicator bacteria, the Oxford cup method was used to determine the antibacterial activity of the indicator bacteria after activating them three times.

[0036] The Oxford cup method was used, specifically as follows: Two generations of activated *Lactobacillus reuteri* Gambol-LR1 was inoculated into MRS broth at a 2% (v / v) inoculum and anaerobically cultured at 37°C for 24 h. The activated pathogenic bacterial suspension was then serially diluted 10-fold, with the 10-fold dilution selected as the final dilution. -2 Prepare the bacterial culture for later use. Seal the bottom of a petri dish with 5 mL of MRS agar medium. After cooling and solidification, evenly distribute Oxford cups. Add 100 μL of indicator bacterial culture to 15 mL of MRS agar at 50-60℃, mix well, and slowly pour into the plate containing the Oxford cups. After solidification, remove the Oxford cups with tweezers to form 8 mm × 6 mm × 10 mm round holes. Add 200 μL of the bacterial fermentation supernatant to the round holes, diffuse at 4℃ for 12 h, and then anaerobically incubate at 37℃ for 9-12 h. Observe for the presence of inhibition and measure the diameter of the inhibition zone with calipers.

[0037] Experimental results are as follows Figure 3 As shown, strain LR1 exhibits strong inhibitory effects against both Gram-positive bacteria (Staphylococcus aureus) and Gram-negative bacteria (Escherichia coli, Porphyromonas gingivalis, Shigella flexneri, and Shigella spp.), with inhibition zones exceeding 10 mm in diameter. The strongest inhibitory effects were observed against Escherichia coli and Staphylococcus aureus, with inhibition zones in the supernatant exceeding 24 mm in diameter.

[0038] Depend on Figure 1 , Figure 2 and Figure 3 The results showed that Gambol-LR1, a strain of Lactobacillus reuteri from desert cats, had good acid resistance, salt resistance, and antibacterial ability, which were higher than those of strains LR2 and LR3.

[0039] Example 2: Identification of Gambol-LR1, a strain of *Lactobacillus reuteri* from the desert cat. Genomic DNA was extracted from the isolated strain using a bacterial genomic extraction kit, and amplified using the universal 16S rDNA forward primer 27F and reverse primer 1495R. The amplified product was then recovered by gel extraction and sequencing. The 16S rDNA sequence of Lactobacillus reuteri Gambol-LR1 from the desert cat is shown in SEQ ID NO:1.

[0040] SEQ ID NO:1 The sequencing results were compared with the gene bank using BLAST on the NCBI website, and the results showed that the desert cat source Gambol-LR1 is a strain of Lactobacillus reuteri.

[0041] The whole genome of Gambol-LR1, a strain of *Lactobacillus reuteri* from the desert cat, was analyzed. The results of the whole genome circos diagram are as follows: Figure 4 As shown.

[0042] Example 3: Based on glycerol and vitamin B 12 In vitro antibacterial synergistic experiment 1. Selection of glycerol concentration In the presence of coenzyme B 12 Against this background, *Lactobacillus reuteri* metabolizes glycerol to produce reuterin (a mixture of 3-hydroxypropionaldehyde), which, by binding to intracellular thiol groups of pathogenic bacteria, disrupts cell membrane integrity and inhibits Gram-negative bacteria (such as *Escherichia coli* and *Salmonella*) as well as some Gram-positive bacteria. To prevent the production of organic acids by *Lactobacillus reuteri* from interfering with the antibacterial effect of reuterin, *Porphyromonas gingivalis*, which can effectively neutralize the surrounding acidic environment locally by producing ammonia (NH3) through amino acid catabolism, was selected as the target pathogen for concentration testing of *Gambol-LR1* *Lactobacillus reuteri* derived from the desert cat, which enhances antibacterial activity through glycerol metabolism.

[0043] Two generations of activated *Lactobacillus reuteri* Gambol-LR1 was inoculated into MRS broth at a 2% (v / v) inoculum and anaerobically cultured at 37°C for 24 h. Glycerol and vitamin B1 were then added at final concentrations of 0 mM, 50 mM, 100 mM, 200 mM, and 400 mM, respectively, with 20 μM added. 12 The bacteria were anaerobic at 37°C for 3 hours, and the supernatant was collected by centrifugation. The activated *Porphyromonas gingivalis* suspension was then serially diluted 10-fold, with the final dilution being 10⁻⁶. -2 Prepare the bacterial culture for later use. Seal the bottom of a petri dish with 5 mL of Columbia blood agar medium. After cooling and solidification, evenly distribute the culture into Oxford cups. Add 100 μL of indicator bacterial culture to 15 mL of Columbia blood agar at 50-60℃, mix well, and slowly pour into the plate containing the Oxford cups. After solidification, remove the Oxford cups with tweezers to form 8 mm × 6 mm × 10 mm circular wells. Add 200 μL of the bacterial fermentation supernatant to each well. Diffusion is performed at 4℃ for 12 h, followed by anaerobic incubation at 37℃ for 36-48 h. Observe for the presence of inhibition and measure the diameter of the inhibition zone with calipers.

[0044] Experimental results are as follows Figure 5As shown, at a glycerol concentration of 200 mM, strain Gambol-LR1 exhibited the strongest inhibitory effect against Porphyromonas gingivalis, with an inhibition zone diameter exceeding 16 mm.

[0045] 2. Add glycerin and vitamin B. 12 Comparison experiment with antibacterial ability without additives The Oxford cup method was used, and the specific method is as follows: Two generations of activated *Lactobacillus reuteri* Gambol-LR1 was inoculated into MRS broth medium at a 2% (v / v) inoculum and anaerobically cultured at 37°C for 24 h. Then, glycerol to a final concentration of 200 mM and vitamin B2 were added. 12 The bacteria were anaerobically cultured at 37°C for 3 hours, and the supernatant was collected by centrifugation. The suspensions of activated pathogenic bacteria (Escherichia coli, Staphylococcus aureus, Porphyromonas gingivalis, Shigella flexneri from cats with cystitis, and Shigella flexneri from cats with cystitis) were serially diluted 10-fold, with the final dilution being 10⁻⁵. -2 Prepare the bacterial culture for later use. Add 5 mL of MRS agar medium to the bottom of the petri dish for sealing. After cooling and solidification, evenly place Oxford cups. Add 100 μL of indicator bacterial culture to 15 mL of MRS agar at 50-60℃, mix well, and slowly pour into the plate containing the Oxford cups. After solidification, remove the Oxford cups with tweezers to form 8 mm × 6 mm × 10 mm round holes. Add 200 μL of the bacterial fermentation supernatant to the round holes. After diffusion at 4℃ for 12 h, anaerobic culture at 37℃ for 9-12 h. Observe for the presence of inhibition and measure the diameter of the inhibition zone with calipers. Compare the culture with the culture without added glycerol and vitamin B. 12 The supernatant was compared with the inhibition zone.

[0046] The results are as follows Figure 6 As shown, when using glycerin and vitamin B... 12 After treatment, the diameter of the inhibition zone increased by more than 35%, with the largest increase observed in Shigella from cats with cystitis, at 75.33%.

[0047] Example 4: Biosafety Experiment 1. Hemolytic activity test of Gambol-LR1 Lactobacillus reuteri from desert cats The activated *Lactobacillus reuteri* Gambol-LR1 strain from desert cats was streaked onto Columbia blood agar plates containing 5% sheep whole blood. The plates were incubated in an anaerobic incubator at 37°C for 24-48 hours, and the presence of clear (β-hemolysis), grass-green (α-hemolysis), or unchanged (γ-hemolysis) hemolytic zones around the colonies was observed.

[0048] like Figure 7As shown, the Gambol-LR1 strain grew well on blood agar plates, with no transparent or grass-green hemolytic zone appearing around the colonies, exhibiting γ-hemolysis (non-hemolytic) characteristics. This indicates that the strain has no erythrolytic ability, possesses good biosafety, and meets the standards for probiotic use.

[0049] 2. Antibiotic susceptibility testing of Gambol-LR1 Lactobacillus reuteri from desert cats The overuse of antibiotics in the pharmaceutical industry can lead to increased drug resistance in pathogenic strains, and the gut microbiota in humans is prone to disorder and imbalance. Therefore, obtaining antibiotic-sensitive lactic acid bacteria has become one of the important indicators of whether their application in food is safe.

[0050] The concentration of the Gambol-LR1 bacterial culture of *Lactobacillus reuteri* from desert cats, cultured for 24 hours, was adjusted to 10. 8 CFU / mL, 100uL of bacterial culture was added to an MRS solid plate, spread evenly, and dried. Four drug sensitivity discs were placed on each plate. After diffusion at 4℃ for 12h, the plates were anaerobically cultured at 37℃ for 9-12h. The results were used to determine the sensitivity of the strain to the drug according to the instructions for use of the drug sensitivity discs.

[0051] The results are shown in Table 1. The desert cat-derived Lactobacillus reuteri Gambol-LR1 was highly sensitive to chloramphenicol, carbenicillin, penicillin, cefazolin, piperacillin, ampicillin, ceftriaxone, cefuroxime, and ceftazidime, but resistant to erythromycin, tetracycline, and lincomycin.

[0052] Table 1. Results of antibiotic susceptibility testing for Lactobacillus reuteri Gambol-LR1 Finally, it should be noted that the above description of the present invention is merely a preferred embodiment and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A strain of *Lactobacillus reuteri* Gambol-LR1 derived from the desert cat, characterized in that... The strain is deposited at the China General Microbiological Culture Collection Center (CGMCC) with accession number CGMCC No. 37228 and deposit date of December 29, 2025. Its 16S rDNA sequence is shown in SEQ ID NO:

1.

2. The *Lactobacillus reuteri* Gambol-LR1 from the desert cat as described in claim 1, characterized in that, The strain exhibits excellent resistance to acid and high bile salt stress at cat body temperature. The survival rate of the strain after 3 hours of stress at 38.5℃ and pH=2 was 444.1%, and the survival rate after 3 hours of stress at 38.5℃ and pH=3 was 422%. The survival rate after 3 hours of stress at 38.5℃ and 0.1% bile salts was 26.2%, and the survival rate after 3 hours of stress at 38.5℃ and 0.2% bile salts was 53.2%.

3. The *Lactobacillus reuteri* Gambol-LR1 derived from the desert cat according to claim 1, characterized in that, The strain exhibits specific antibacterial activity against both Gram-positive and Gram-negative bacteria. The inhibited bacteria include *Escherichia coli*, *Staphylococcus aureus*, *Salmonella*, *Porphyromonas gingivalis*, *Shigella flexneri* (from cats with cystitis), and *Shigella flexneri* (from cats with cystitis). Specifically, the inhibition zone diameter against *Staphylococcus aureus* is 24.6 mm, against *Escherichia coli* is 27.4 mm, against *Porphyromonas gingivalis* is 11.4 mm, against *Shigella flexneri* (from cats with cystitis) is 20.1 mm, and against *Shigella flexneri* (from cats with cystitis) is 22.7 mm.

4. The *Lactobacillus reuteri* Gambol-LR1 derived from the desert cat according to claim 1, characterized in that, The strain has no hemolytic activity and high biosafety; it is also sensitive to a variety of antibiotics, including chloramphenicol, carbenicillin, penicillin, cefazolin, piperacillin, ampicillin, ceftriaxone, cefuroxime, and ceftazidime.

5. The *Lactobacillus reuteri* Gambol-LR1 from the desert cat as described in claim 1, characterized in that, The strain can react with glycerol and vitamin B. 12 Synergistic effect significantly enhances antibacterial ability; added glycerin and vitamin B 12 After treatment, the diameter of the inhibition zone of the strain against Staphylococcus aureus, Escherichia coli, Porphyromonas gingivalis, Shigella flexneri from cats with cystitis, and Shigella flexneri from cats with cystitis increased by 43.09%, 47.81%, 46.49%, 39.80%, and 75.33%, respectively.

6. A probiotic preparation, characterized in that, It contains at least one of the following: Gambol-LR1 of the desert cat-derived Lactobacillus reuteri according to any one of claims 1-5, and its metabolites.

7. A cat health product, characterized in that, The health product is an animal food, health supplement, or medicine, containing *Lactobacillus reuteri* Gambol-LR1 from the desert cat as described in any one of claims 1-5 and / or the probiotic agent as described in claim 6.

8. The use of the Pallas's cat-derived Lactobacillus reuteri Gambol-LR1 as described in any one of claims 1-5 in the preparation of cat anti-infective and intestinal microecological regulation health products.

9. The application according to claim 8, characterized in that, The health products are used to prevent and treat periodontal disease, bacterial enteritis, and secondary urinary tract infections in cats.

10. The application according to claim 8, characterized in that, The strain can adapt to and stably colonize the extreme environment of strong acid and high bile salt in the cat's digestive tract. It can efficiently produce reuterin in situ in the cat's body, achieving continuous antibacterial protection of live bacteria and avoiding the limitations of using in vitro purified reuterin as a chemical additive.

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