Phage of a lytic salmonella blegdam and compositions and uses thereof

Abstract

The present application relates to the technical field of Salmonella bacteriophage, and particularly relates to a bacteriophage capable of lysing Salmonella Blegdam (Salmonella Blegdam bacteriophage) and a composition and application thereof. The bacteriophage is Salmonella bacteriophage RDP-SA-22010, the preservation number of which is CGMCC No. 45274, and the bacteriophage was preserved in the China General Microbiological Culture Collection Center on September 21, 2022. The Salmonella bacteriophage RDP-SA-22010 can also lyse Salmonella enteritidis, Salmonella pullorum and Salmonella kentucky. A composition comprises the Salmonella bacteriophage RDP-SA-22010. A reagent or kit comprises the above-mentioned composition. The present application also provides that the Salmonella bacteriophage RDP-SA-22010 can be applied to the preparation of a biological sterilizing agent, the preparation of a medicine for treating diseases caused by Salmonella and the preparation of a feed additive. The Salmonella bacteriophage RDP-SA-22010 in the present application provides a new biological control means for the prevention and treatment of Salmonella Blegdam.

Description

Technical Field

[0001] This invention relates to the field of Salmonella phage technology, specifically to a phage capable of lysing Salmonella brigidae, its composition, and its applications. Background Technology

[0002] Salmonella is a major pathogen causing food poisoning in livestock and humans, posing a serious threat to livestock farming and human health. Traditional methods of Salmonella control mainly rely on antibiotics and chemical disinfectants, but these methods have problems such as drug residues, environmental pollution, and drug resistance. Bacteriophages, as naturally occurring bacterial viruses, have the ability to specifically lyse host bacteria and are therefore widely used in biological control.

[0003] In recent years, food poisoning incidents caused by Salmonella britanea have occurred frequently, with the detection rate increasing year by year. Clinical symptoms after poisoning include high fever, abdominal pain, diarrhea, nausea, and vomiting. Symptoms in poultry infected with Salmonella enteritidis are similar, including lethargy, drooping head and closed eyes, drooping wings, ruffled feathers, significant anorexia, increased water intake, watery diarrhea, feces stuck to the anus, and a tendency to avoid heat sources or crowd together. Because of these similar symptoms, misdiagnosis is very easy, leading to delays in optimal treatment and significant losses. Furthermore, animals carrying Salmonella britanea are prone to cross-contamination during slaughter, causing food poisoning. This pathogen can spread horizontally and vertically throughout the entire breeding cycle. This is extremely detrimental to poultry farming and human food health and safety.

[0004] Currently, there are no phages available on the market specifically targeting Salmonella britanea. Therefore, effective phages targeting Salmonella britanea still need to be developed. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a bacteriophage RDP-SA-22010 targeting Salmonella britanea. Furthermore, the Salmonella bacteriophage RDP-SA-22010 of this invention can not only lyse Salmonella britanea, but also has a good lysing effect on Salmonella enteritidis, Salmonella pullorum, and Salmonella Kentuckyis.

[0006] The technical solution of this invention is as follows:

[0007] A bacteriophage capable of lysing Salmonella Blegdam, specifically Salmonella bacteriophage RDP-SA-22010, with accession number CGMCC No. 45274, was deposited at the China General Microbiological Culture Collection Center on September 21, 2022.

[0008] In another aspect, the Salmonella bacteriophage RDP-SA-22010 can also lyse Salmonella enteritidis, Salmonella pullorum and Salmonella kentucky.

[0009] In another aspect, the Salmonella bacteriophage RDP-SA-22010 in the present application has a full-length genome sequence of 43035 bp, and has 59 open reading frames, and no genes related to lysogeny, antibiosis, virulence or toxin-antitoxin are detected.

[0010] In another aspect, the Salmonella bacteriophage RDP-SA-22010 in the present application can be seen from the electron micrograph that the bacteriophage is a long-tailed bacteriophage, the head is a regular hexagon, the head diameter is about 65 nm, and the tail length is 105 nm.

[0011] In another aspect, the Salmonella bacteriophage RDP-SA-22010 in the present application has good stability at a temperature of 50-70℃ and a pH of 5-10. The titer of the Salmonella bacteriophage RDP-SA-22010 in the present application can be maintained at more than 10 8 pfu / mL under the condition of a temperature of 80℃ for 5 min; and still has activity under the condition of a temperature of 80℃ for 15 min.

[0012] In another aspect, the titer of the Salmonella bacteriophage RDP-SA-22010 in the present application can be more than 10 11 pfu / mL.

[0013] In another aspect, the Salmonella bacteriophage RDP-SA-22010 in the present application has a latent period of 5 min and a burst period of 50 min.

[0014] In another aspect, the titer of the Salmonella bacteriophage RDP-SA-22010 in the present application can be maintained at more than 10 9 pfu / mL after the bacteriophage is stored for 24 months under the condition of 4℃ without any treatment, and the titer of the Salmonella bacteriophage RDP-SA-22010 can be maintained at the same order of magnitude under the condition of -80℃ and lyophilization.

[0015] In another aspect, the optimal infection multiple of the Salmonella bacteriophage RDP-SA-22010 in the present application is 0.01.

[0016] Based on the same inventive concept, the present application provides a composition comprising the Salmonella bacteriophage RDP-SA-22010.

[0017] Based on the same inventive concept, the present application provides a reagent or kit comprising the above-mentioned composition.

[0018] Based on the same inventive concept, the application provides the application of the above-mentioned Salmonella bacteriophage RDP-SA-22010, which can be applied to the preparation of biological sterilizing agent, the preparation of drugs for treating diseases caused by Salmonella and the preparation of feed additives.

[0019] Based on the same inventive concept, the application provides that the Salmonella bacteriophage RDP-SA-22010 can be applied to the preparation of biological sterilizing agent for Salmonella blegdam, the preparation of drugs for treating diseases caused by Salmonella blegdam and the preparation of feed additives for Salmonella blegdam.

[0020] Based on the same inventive concept, the application provides that the Salmonella bacteriophage RDP-SA-22010 can be used as a daily sterilizing agent, can specifically kill Salmonella in the environment, and improve the microbial distribution in the environment. It can also be used as a biological sterilizing agent for livestock and poultry product breeding, transportation and preservation, for preventing and treating pathogenic Salmonella pollution in the process of livestock and poultry breeding, transportation and preservation. It can also be used in combination with other sterilizing agents to be sprayed in food production workshops to prevent and treat Salmonella pollution in the food processing process.

[0021] Based on the same inventive concept, the application provides that the Salmonella bacteriophage RDP-SA-22010 can be added to feed, can specifically and continuously prevent the survival and reproduction of Salmonella in feed, and prevent Salmonella pollution in feed storage and animal breeding.

[0022] Preservation information: the Salmonella bacteriophage RDP-SA-22010 has a preservation number of CGMCC No.45274 and was preserved in the China General Microbiological Culture Collection Center on September 21, 2022

[0023] The application achieves the following beneficial effects:

[0024] 1. The Salmonella bacteriophage RDP-SA-22010 in the application can lyse Salmonella blegdam, treat or prevent diseases and biological environment pollution caused by Salmonella blegdam. The titer of the Salmonella bacteriophage RDP-SA-22010 in the application can be 10 11 pfu / mL or more, which provides a reliable biological control bacteriophage for Salmonella blegdam.

[0025] 2. The Salmonella bacteriophage RDP-SA-22010 in the application can also be used to lyse Salmonella enteritidis, Salmonella gallinarum and Salmonella kentucky, and has a wide range of applications.

[0026] 3、The Salmonella bacteriophage RDP-SA-22010 in the application has good thermal stability and tolerance, and the titer is maintained at more than 10 4 pfu / mL after water bath at 70 DEG C for 60 min, is still high, and the titer is maintained at more than 10 8 pfu / mL after maintaining at 80 DEG C for 5 min; and still has activity after maintaining at 80 DEG C for 15 min.

[0027] 4、The Salmonella bacteriophage RDP-SA-22010 in the application has good pH stability and wide tolerance, is stable between pH 5-10, and still has activity after maintaining at pH 2 for 2 h.

[0028] 5、The Salmonella bacteriophage RDP-SA-22010 in the application still has a titer of 10 9 pfu / mL after storing at 4 DEG C for 24 months without any treatment, and the titer of the Salmonella bacteriophage RDP-SA-22010 is maintained at the same order of magnitude after storing at-80 DEG C and freeze-drying.

[0029] 6、The optimal infection multiple of the Salmonella bacteriophage RDP-SA-22010 in the application is 0.01.

[0030] 7、The latent period of the bacteriophage RDP-SA-22010 in the application is 5 min, and the latent period is short. Then the titer of the bacteriophage increases sharply, and remains stable after 60 min. The burst period of the bacteriophage is 50 min, and the host cell can be quickly lysed. The lysis amount is the ratio of the titer of the bacteriophage at the end of lysis to the amount of the host bacteria at the beginning of infection, and the lysis amount of the bacteriophage RDP-SA-22010 is 72 PFU / cell.

[0031] 8、The Salmonella bacteriophage RDP-SA-22010 in the application can be applied to the preparation of biological sterilizing agent, the preparation of medicine for treating diseases caused by Salmonella and the preparation of feed additive, so as to replace the application of antibiotics in the prevention and treatment of livestock and poultry breeding, and has high efficiency and economy in practical application. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 It is the plaque map of the Salmonella bacteriophage RDP-SA-22010 in the application.

[0033] Figure 2 It is the electron microscope graph of the Salmonella bacteriophage RDP-SA-22010 in the application.

[0034] Figure 3 It is the one-step growth curve of the Salmonella bacteriophage RDP-SA-22010 in the application.

[0035] Figure 4 Figure 4 is a graph of the effect of temperature on the titer of the Salmonella bacteriophage RDP-SA-22010 of the present application.

[0036] Figure 5 Figure 5 is a graph of the effect of temperature at 80°C on the titer of the Salmonella bacteriophage RDP-SA-22010 of the present application.

[0037] Figure 6 Figure 6 is the results of the pH stability of the Salmonella bacteriophage RDP-SA-22010 of the present application.

[0038] Figure 7 Figure 7 is the inhibition curve of the Salmonella bacteriophage RDP-SA-22010 of the present application.

[0039] Figure 8 Figure 8 is the genome map of the Salmonella bacteriophage RDP-SA-22010 of the present application. DETAILED DESCRIPTION

[0040] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the contents in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0041] Unless otherwise defined, all technical and scientific terms used in the present application have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description of the application herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. All publications, patent applications, patents, and other references mentioned in this specification are incorporated by reference. In case of a conflict in terminology, the present specification controls. In this specification, the use of "and / or" means

[0042] The experimental methods used in the following examples are conventional methods unless otherwise specified.

[0043] The materials, reagents and the like used in the following examples are commercially available unless otherwise specified.

[0044] The following Salmonella bacteriophage RDP-SA-22010 or is simply referred to as "bacteriophage RDP-SA-22010" or "RDP-SA-22010".

[0045] Example 1: Isolation and identification of Salmonella

[0046] Samples were taken from the livers of diseased chickens. Using aseptic techniques, samples were streaked onto SS agar (Salmonella-Shigella agar) and incubated at 37°C for 20 hours. The resulting colonies on SS agar were neat, with black centers and white edges, approximately 2–3 mm in diameter. Typical colonies were then streaked onto LB (Luria-Bertani) agar and incubated at 37°C for 20 hours. The colonies showed diffuse growth on LB agar plates. Typical colonies were streaked three more times for purification. Then, single colonies were inoculated into 5 mL of LB liquid medium and incubated at 37°C with shaking at 200 rpm for 8 hours, yielding a homogeneous, turbid bacterial suspension. 16S rRNA molecular identification confirmed the bacteria as Salmonella.

[0047] Using a complete set of Salmonella biochemical identification tubes (Qingdao Haibo Biotechnology Co., Ltd.), biochemical identification was performed according to the instructions, showing a positive reaction kinetics, acid production, gas production, and hydrogen sulfide production. Serological identification was performed using a Salmonella diagnostic serological kit (Ningbo Tianrun Biopharmaceutical Co., Ltd.) according to the instructions. The AF multivalent serum agglutination test showed (++++), and the bacterial O9 antigen (++++), O12 antigen (++++), and flagellar H antigen m and q were all (+++). Based on the above test results, the final diagnosis was Salmonella Britannia.

[0048] Example 2: Isolation and Identification of Bacteriophages

[0049] (1) Sampling

[0050] The sample used in this invention was collected from wastewater surrounding a farm in Liaoning Province in 2024, serving as the water sample for phage isolation. 10 mL of wastewater was centrifuged at 10,000 rpm for 5 min to remove larger impurities and most bacteria, then filtered through a 0.22 μm microporous membrane for sterilization. 3 mL of the filtrate and 3 mL of the host bacterial suspension were added together to 20 mL of autoclaved LB broth, and then incubated overnight at 37°C. After incubation, 5 mL of the filtrate was centrifuged at 10,000 rpm for 5 min, and then filtered through a 0.22 μm microporous filter for sterilization; the filtrate was the stock solution intended to contain phages. The presence of phage plaques was then used to identify the presence of phages; the absence of plaques indicated the presence of phages, while the absence of plaques indicated that no phages were isolated, requiring further screening.

[0051] (2) Purification of bacteriophages

[0052] The primary isolated phage plaques are often inconsistent in size and morphology, thus further purification is required. A single independent, uniform in morphology, clear and transparent plaque is picked from the double-layer plate with plaques, immersed in 1 mL of normal saline for 10 min, and the supernatant is filtered through a 0.22 μm microporous filter. The filtrate is then appropriately diluted (a single plaque is formed on a double plate) and plated with a host bacterial suspension. This step is repeated 3-4 times until the plaques on the double plate are uniform in size, morphology and clarity. As shown in Fig. 1, the plaques are uniform in size, morphology and clarity, and have the typical characteristics of lytic phages. Figure 1

[0053] (3) Determination of phage titer

[0054] The purified phage is plated on a double-layer plate, and a single plaque is picked and added to LB liquid medium with a host bacterial suspension. The phage is propagated, and the propagation liquid is centrifuged at 10,000 rpm for 5 min and then filtered through a 0.22 μm microporous filter. The filtrate is diluted by a factor of 10 to 10 8 times, and 0.1 mL of the phage dilution and 0.1 mL of the host bacterial suspension at each of the last three dilution levels are plated on a double-layer plate to determine the phage titer.

[0055] Phage titer (pfu / mL) = plaque number * dilution factor ÷ 0.1

[0056] The titer of the phage can be up to 10 11 pfu / mL or more.

[0057] Example 3: Morphological observation of Salmonella phage RDP-SA-22010

[0058] Phosphotungstic acid negative staining method: 100 μL of the phage liquid (titer 10 10 pfu / mL) is dropped on a paraffin slice, the membrane side of a copper mesh is placed on the phage liquid drop, and after 10 min, the copper mesh is removed and naturally dried in air for 2-3 min. A drop of 2% phosphotungstic acid (PTA) aqueous solution is dropped on the copper mesh for staining, and after 10 min, the copper mesh is removed and dried in air for 10-15 min. The phage images are observed under an electron microscope, and clear phage images are selected for photography. As shown in Fig. 2, the phage is a long-tailed phage with a regular hexagonal head, a head diameter of about 65 nm, and a tail length of 105 nm. Figure 2

[0059] Example 4: One-step growth curve of Salmonella phage RDP-SA-22010

[0060] ​​Salmonella phage RDP-SA-22010 and host bacteria were mixed at the optimal MOI value and incubated at 37°C for 10 min to allow the phage to adsorb onto the host bacteria. The mixture was then centrifuged at 10000 rpm for 5 min, the supernatant was discarded, and the phage was resuspended in an equal volume of LB broth. This process was repeated twice to remove any unadsorbed phage. 10 mL of the above liquid was added to 90 mL of LB broth. Samples of 1 mL were taken at regular intervals (i.e., samples at 0 min, 10 min, 20 min, 30 min, 40 min, 50 min, 60 min, 90 min, 120 min, 150 min, 180 min, and 240 min) and centrifuged at 10000 rpm for 5 min. The supernatant was then used to determine the phage titer using the double-layer plate method.

[0061] Depend on Figure 3 As shown, the curve trend of bacteriophage RDP-SA-22010 remained stable in the first 5 minutes, indicating a short latency period of 5 minutes. Afterwards, the phage titer increased sharply and remained stable after 60 minutes, with a burst phase of 50 minutes, demonstrating its ability to rapidly lyse host cells. The lysis yield, calculated as the ratio of the phage titer at the end of lysis to the host bacterial load at the initial stage of infection, was determined to be 72 PFU / cell for bacteriophage RDP-SA-22010.

[0062] Example 5: Thermal stability of Salmonella phage RDP-SA-22010

[0063] The phage titer was adjusted to 10. 9 The concentration of pfu / mL was then aliquoted into 1.5mL centrifuge tubes, with 1mL added to each tube. The aliquoted phage solutions were then incubated in water at 50℃, 60℃, 70℃, and 80℃ for 30min, respectively. After the water bath, double-layer plates were laid to determine the phage titer.

[0064] Depend on Figure 4 As shown, bacteriophage RDP-SA-22010 achieved a titer of 10 after a water bath at 70°C for 60 minutes. 4 At concentrations above pfu / mL, the potency remains high. For example... Figure 5 As shown, the titer of bacteriophage RDP-SA-22010 remained at 10 for 5 minutes at 80°C. 8 The phage RDP-SA-22010 exhibits good temperature tolerance, remaining active even after being kept at 80℃ for 15 minutes, with a concentration of pfu / mL or higher.

[0065] Example 6: pH stability of Salmonella phage RDP-SA-22010

[0066] Take 100μL, potency is 10 9 Phage suspensions of pfu / mL were added to 900 μL of phosphate buffer solutions with different pH values ​​(2–13), and the solutions were placed in a 37°C water bath for 2 h. After that, double-layer plates were laid and the titer of the phages in each centrifuge tube was determined.

[0067] Depend on Figure 6 As shown, bacteriophage RDP-SA-22010 is relatively stable between pH 5 and 10, and retains its activity after being maintained at pH 2 for 2 hours. Therefore, this bacteriophage has a wide tolerance to pH.

[0068] Example 7: Preservation method of Salmonella bacteriophage RDP-SA-22010

[0069] The valence is 10 11 The pfu / mL phage solution was first centrifuged at 10000 rpm for 5 min, then sterilized using a 0.22 μm filter. Three preservation methods were then employed: First, preservation at 4°C: 1 mL of sterile phage RDP-SA-22010 solution was aliquoted into 2 mL cryovials and stored at 4°C. Second, cryopreservation: 1 mL of phage RDP-SA-22010 solution was mixed with 60% glycerol (60 g glycerol + 40 g LB broth) at a 1:1 ratio, aliquoted into 2 mL cryovials, and stored at -80°C. The third method involved mixing phage RDP-SA-22010 solution with a lyophilization protectant (5g skim milk powder, 2g mannitol, and 100mL water) in a 1:1 ratio, dispensing the mixture into 400µL ampoules, dehydrating them using a lyophilizer, and finally sealing and storing them at 4°C. The titer of phage RDP-SA-22010 was measured every 3 months. The results are shown in the table below.

[0070] Table 1: Changes in titer of phage RDP-SA-22010 under different preservation conditions

[0071]

[0072] Note: Unit is *10 9 pfu / mL

[0073] As shown in Table 1, the phage RDP-SA-22010 is relatively stable. After being stored at 4℃ without any treatment for 24 months, the phage titer still remained at 10. 9 The phage titer remained unchanged at the same order of magnitude under ultra-low temperature and lyophilization conditions, with a pfu / mL concentration.

[0074] Example 8: Determination of the optimal multiplicity of infection

[0075] MOI refers to the ratio of the number of bacteriophages to the number of host bacteria at the initial infection. The bacteriophages and host bacteria are mixed at a certain MOI value (0.001, 0.01, 0.1, 1, 10, 100, 1000), and then cultured at 37°C and 160 rpm for 6 hours on a shaking table. After the end of the culture, the supernatant is obtained by centrifugation at 10000 r / min for 5 min, and the bacteriophage titer of the supernatant in the sample with different MOI values is determined by the double-layer plate method.

[0076] Table 2: Bacteriophage titer of the supernatant in the sample with different MOI values:

[0077] MOI Phage titer ( * 10 8 pfu / mL)]]> 0.001 351 0.01 1020 0.1 540 1 198 10 224 100 95 1000 71

[0078] As shown in Table 2 above, the bacteriophage RDP-SA-22010 has the highest bacteriophage titer of 1.02×10 11 PFU / mL when the MOI is 0.01, and thus the optimal MOI of the bacteriophage RDP-SA-22010 is 0.01.

[0079] Example 9: Lysis spectrum experiment of the Salmonella bacteriophage RDP-SA-22010

[0080] The lysis spectrum experiment of the Salmonella bacteriophage RDP-SA-22010 in the present application on Salmonella enteritidis, Salmonella pullorum, Salmonella kentucky, Salmonella dublin, Salmonella typhi, Salmonella indiana and Salmonella blegdam is carried out, and the experimental results are shown in the following table:

[0081] Table 3: Lysis spectrum of the Salmonella bacteriophage RDP-SA-22010

[0082] Salmonella lysis ability Salmonella enteritidis + Salmonella gallinarum + Salmonella kentucky + Salmonella dublin - Salmonella typhi - Salmonella indiana - Salmonella blegdam +

[0083] Note: "+" indicates that it can be lysed, and "-" indicates that it cannot be lysed

[0084] As shown in the experimental results of Table 3 above, the Salmonella bacteriophage RDP-SA-22010 of the present application not only can lyse Salmonella blegdam, but also has good lysis effect on other serotypes of Salmonella, such as Salmonella enteritidis, Salmonella pullorum and Salmonella kentucky.

[0085] Example 10: Determination of bacteriostatic curve of the Salmonella bacteriophage RDP-SA-22010

[0086] First, 100 μL of host bacteria and bacteriophage RDP-SA-22010 were mixed according to the best MOl, incubated at 37°C for 10 min, and then inoculated into 5 mL of LB broth medium. Seven groups of samples were prepared and cultured in a 37°C shaking incubator at 160 rpm. The OD value at 600 nm was measured every hour.

[0087] By Figure 7 The experimental results show that, compared with the positive control without bacteriophage RDP-SA-22010, the bacteriophage RDP-SA-22010 has an inhibitory effect on the growth of different Salmonella within 10 h. Among them, it has a strong bacteriostatic effect on Bli Dan Salmonella.

[0088] Example 11: Whole genome sequencing of Salmonella bacteriophage RDP-SA-22010

[0089] After enrichment culture of a single bacteriophage, centrifugation at 8000 g for 15 min at 4°C, addition of 10% PEG8000 and 0.5M NaCl overnight, mixing with an equal amount of chloroform, standing for stratification, centrifugation at 5000 g for 10 min, removal of the chloroform layer and PEG layer, addition of restriction endonuclease digestion, and suspension of the bacteriophage under gradient density cesium chloride conditions, the bacteriophage was dialyzed in TM (Temperature Melting) buffer for 3 times, 30 min each time. Finally, part of the dialyzed bacteriophage was reserved for electron microscope observation, and part was sent to Huada Gene Bio-sequencing Company for whole genome sequencing. The bacteriophage sequence is shown as SEQ ID NO. 1. The genome map is shown as Figure 8 The whole genome sequence of the bacteriophage RDP-SA-22010 is 43035 bp, and there are 59 open reading frames. No genes encoding lysogeny, antibacterial, virulence or toxin-antitoxin related genes were detected.

[0090] Example 12: Chicken embryo protection experiment

[0091] The experiment selects 1-week-old chicken embryos, and divides into 3 groups, 100 chicken embryos in each group, one group is blank control group, the chicken embryos in the group are injected with 0.2 mL LB broth; one group is Brilidan Salmonella challenge group, the chicken embryos in the group are injected with 0.1 mL Salmonella liquid and 0.1 mL LB broth; one group is treatment group, the chicken embryos in the group are injected with 0.1 mL Salmonella liquid and 0.1 mL phage liquid. After treatment, the embryos are placed in an incubator for incubation, and the number of deaths and the hatching rate are recorded. Then, the 7-day-old chicks hatched are aseptically dissected to obtain livers and ground, and the ground liquid is inoculated into selenite cysteine enrichment liquid (SC enrichment liquid) at a proportion of 10%, and then cultured at 37°C for 20 h. Then, the culture liquid is inoculated on SS agar, and after inoculation, the plate is placed in a 37°C incubator for 20 h, and whether Salmonella is observed.

[0092] Table 4: Results of chicken embryo protection experiment

[0093] Number of deaths Hatchability Salmonella detection rate Blank group 20 80 0 Challenge group 90 10 100％ Treatment group 30 70 0

[0094] As can be seen from the experimental results in Table 4, no Salmonella is detected in the hatched chickens in the treatment group, indicating that the Salmonella phage RDP-SA-22010 has a good treatment effect on the disease caused by Brilidan Salmonella.

[0095] The above-described embodiments of the present application do not constitute a limitation on the protection scope of the present application. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present application shall be included in the protection scope of the claims of the present application.

Claims

1. A bacteriophage of Salmonella Blegdam, which is characterized in that: The bacteriophage is a Salmonella bacteriophage , and the deposit number is CGMCC No. 45274, which was preserved in China General Microbiological Culture Collection Center on September 21, 2022.

2. The bacteriophage of lytic Bredan Salmonella of claim 1, characterized in that: The bacteriophage of Salmonella Salmonella enteritidis, Salmonella gallinarum and Salmonella kentucky can also be lysed.

3. The bacteriophage of lytic Bredenella salmonis according to claim 1, characterized in that: The bacteriophage of Salmonella The titer was maintained at 10 8 pfu / mL for 5 min at 80°C; it remained active for 15 min at 80°C.

4. The bacteriophage of lytic Bredenella salmonis according to claim 1, characterized in that: The phage of Salmonella The phage of Salmonella 9 pfu / mL, under conditions of storage at -80°C and lyophilization, the phage of Salmonella maintained at the same order of magnitude.

5. The bacteriophage of lytic Bredan Salmonella of claim 1, characterized in that: The titer of the said Salmonella bacteriophage may reach 10 11 pfu / mL or above, the latent period is 5 min, and the burst period is 50 min.

6. The bacteriophage of lytic Bredenella salmonis according to claim 1, characterized in that: The salmonella phage The optimal multiplicity of infection is 0.

01.

7. A bacteriophage of the lytic Bredeney Salmonella bacterium according to claim 1, characterized in that: The said Salmonella phage It can be applied to the preparation of biological fungicides against Salmonella blegdam, the preparation of drugs for the treatment of diseases caused by Salmonella blegdam and the preparation of feed additives against Salmonella blegdam.

8. A composition characterized in that: Salmonella phage according to claim 1 or 2 .

9. A reagent or kit comprising the composition of claim 8.

Images