Shewanella alginate bacteriophage composition with broad-spectrum splitting activity and application of shewanella alginate bacteriophage composition

Abstract

The invention provides an algal shewanella and bacteriophage composition and application thereof, and belongs to the technical field of microbial control. According to the invention, two new strains of strong shewanella alga bacteriophages are obtained through screening, have strong host specificity and strong splitting decomposition and killing effects on shewanella alga, and meanwhile, when the two strains of strong shewanella alga bacteriophages are mixed for use, the shewanella alga can be effectively prevented from generating resistance mutation, so that an ideal pathogenic bacterium removal effect is achieved, and the application prospect is wide. Therefore, the method has an important application value in the aspect of preventing and controlling infectious diseases of the shewanella alginate of marine aquaculture animals.

Description

Technical Field

[0001] The invention belongs to the technical field of microbial control, and in particular relates to a phage composition of Shewanella algae with broad-spectrum lytic activity and application thereof. Background Art

[0002] Shewanella algae is a Gram-negative bacterium that is widely distributed in natural environments such as oceans, seawater and beaches. The bacterium can cause infectious lesions in fish and shrimp, with significant external symptoms and even death. Common symptoms include skin lesions, ascites and gill inflammation. In addition, infection with Shewanella algae may damage the immune system of fish and shrimp, thereby increasing their mortality rate, posing a huge threat to the aquaculture industry.

[0003] More seriously, Shewanella algae may be transmitted to humans through contaminated seafood, causing gastrointestinal infections, manifested as diarrhea, nausea, vomiting, abdominal pain, etc. In view of this, effectively solving the infection problem of Shewanella algae in aquaculture not only has a far-reaching impact on economic development, but is also crucial to protecting human health.

[0004] In aquaculture, people have traditionally relied on antibiotics to solve the problem of Shewanella algae infection. However, the long-term and widespread use of antibiotics can lead to the emergence of multidrug-resistant strains, which increases the risk of disease infection in farmed fish and shrimp, significantly increases the cost of farming, and makes disease prevention and control more complicated. In addition, excessive use of antibiotics may also inhibit or kill beneficial microorganisms, destroy the microecological balance inside and outside aquatic animals, and then cause the deterioration of the microbial community structure and the obstruction of digestion and absorption function. In view of these problems, there is an urgent need to develop a safe and efficient alternative to antibiotics to combat Shewanella algae infection. In the past two decades, bacteriophages have been valued for their unique antibacterial properties, such as high specificity and good safety, and have gradually become a new type of antibacterial agent actively explored by the pharmaceutical industry.

[0005] Although phage preparations have significant antibacterial potential, they also face some challenges. The most important is that a single phage can only effectively eliminate pathogens in the initial stage of use. However, as time goes on, the pathogens will develop resistance to the phage and show "rebound growth", which makes the phage "ineffective". In addition, the host range of many phages is narrow, making it difficult to cover the various pathogens in the actual environment. Phage cocktails are phage preparations that combine multiple strains of phage through rational design. Phage cocktail therapy is expected to overcome the resistance of pathogens to phages and may expand the host range of phage preparations. Summary of the invention

[0006] In view of the above-mentioned deficiencies in the prior art, the present invention provides a phage composition of Shewanella algae with broad-spectrum lytic activity and application thereof.

[0007] The present invention is achieved through the following technical solutions:

[0008] A bacteriophage composition of Shewanella algae with broad-spectrum lytic activity, comprising bacteriophage Sal P* and bacteriophage Sal M1P1.

[0009] The wild strain phage Sal P* of Shewanella algae has been sent to China Center for Type Culture Collection (address: Wuhan University, Luojia Mountain, Wuchang, Wuhan City, Hubei Province), with a preservation date of July 22, 2024, a preservation number of CCTCC M 20241643, and a classification name of Shewanella alga phage Sal P*.

[0010] The mutant phage Sal M1P1 of Shewanella algae has been sent to the China Center for Type Culture Collection (address: Wuhan University, Luojia Mountain, Wuchang, Wuhan City, Hubei Province), with a preservation date of July 22, 2024, a preservation number of CCTCC M20241644, and a classification name of Shewanella alga phage Sal M1P1.

[0011] The titers of the bacteriophages Sal P* and Sal M1P1 are not less than 10 8 PFU / ml.

[0012] The multiplicity of infection (MOI) was 0.1.

[0013] The invention discloses an application of a bacteriophage composition of Shewanella algae with broad-spectrum lytic activity in preparing a Shewanella algae fungicide.

[0014] The bacteriophage composition is used in preparing a bacterial agent for controlling Vibrio infection in aquaculture.

[0015] A Shewanella algae fungicide, comprising the Shewanella algae bacteriophage composition.

[0016] The formulation of the Shewanella algae fungicide is wettable powder, water dispersible granules or water suspension.

[0017] An application of the seaweed Shewanella fungicide, and application of the seaweed Shewanella fungicide in controlling Vibrio infection in aquaculture.

[0018] Beneficial effects of the present invention:

[0019] The present invention screens and obtains two new strains of virulent seaweed Shewanella phages, which have strong host specificity and strong lysis and killing effects on seaweed Shewanella. At the same time, by combining the two strains of phages, it is found that it can not only achieve a high-efficiency and long-lasting bactericidal effect, but also effectively avoid the problem that pathogens are prone to phage-resistant mutations during phage therapy, and can be widely used in the aquaculture industry, so it has good practical application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0021] Figure 1 : A plate culture photo of the wild strain of Shewanella algae phage Sal P* in Example 2;

[0022] Figure 2 : A plate culture photograph of the mutant phage Sal M1P1 of Shewanella algae in Example 5;

[0023] Figure 3 : Transmission electron microscope photo of the wild-type bacteriophage Sal P* of Shewanella algae in Example 8;

[0024] Figure 4 : Transmission electron micrograph of the mutant phage Sal M1P1 of Shewanella algae in Example 8;

[0025] Figure 5 : Result of the chloroform sensitivity test of wild-type Shewanella algae phage Sal P* in Example 9;

[0026] Figure 6 : Graph showing the results of the chloroform sensitivity test of Shewanella algae mutant phage Sal M1P1 in Example 10;

[0027] Figure 7 : One-step growth curve of wild-type Shewanella algae phage Sal P* in Example 13;

[0028] Figure 8 : One-step growth curve of Shewanella algae mutant phage Sal M1P1 in Example 14;

[0029] Fig. 9 : Evaluation of bacteriocidal effect of phage cocktail when MOI = 0.1; DETAILED DESCRIPTION

[0030] It should be noted that the following detailed descriptions are all illustrative and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0031] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof. It should be understood that the scope of protection of the present invention is not limited to the specific embodiments described below; it should also be understood that the terms used in the embodiments of the present invention are intended to describe specific embodiments, rather than to limit the scope of protection of the present invention.

[0032] As mentioned earlier, phage therapy has certain limitations. For example, pathogenic bacteria can easily develop resistance mutations to infection with a single phage, affecting its actual therapeutic effect.

[0033] The phage cocktail of the present invention can lyse seven types of Vibrio, including Vibrio cannelli, Vibrio alginolyticus, Vibrio parahaemolyticus, Vibrio mytilus, etc., and has a wider host range. In addition, the cocktail can effectively prevent the "rebound growth" of Shewanella algae, thereby achieving an ideal pathogen removal effect, and therefore has important application value in the prevention and control of Shewanella algae infectious diseases in marine aquaculture animals.

[0034] In view of this, in a specific embodiment of the present invention, a Shewanella phage of algae is provided, wherein the Shewanella phage of algae is Shewanella phage of algae Sal P* or Shewanella phage of algae Sal M1P1.

[0035] Among them, the wild strain phage Sal P* of Shewanella algae has been sent to the China Center for Type Culture Collection (address: Wuhan University, Luojia Mountain, Wuchang, Wuhan City, Hubei Province), with a preservation date of July 22, 2024 and a preservation number of CCTCC M 20241643;

[0036] The biological characteristics of the Sal P* described in the present invention are as follows: under an electron microscope, Sal P* appears to be composed of a regular hexahedral head with a diameter of about 51 nm and a tail with a length of 331 nm and a width of 20 nm, and belongs to the family Myocaudatus.

[0037] The Sal P* of the present invention is insensitive to both 2% and 20% chloroform.

[0038] The infection characteristics of the Sal P* of the present invention are as follows: the incubation period of Sal P* infecting the wild strain of Shewanella algae is 15 minutes, the lysis period is 75 minutes, and the phage release amount is 30 PFU / cell.

[0039] The mutant phage Sal M1P1 of Shewanella algae has been sent to the China Center for Type Culture Collection (address: Wuhan University, Luojia Mountain, Wuchang, Wuhan City, Hubei Province), with a preservation date of July 22, 2024 and a preservation number of: CCTCC M20241644.

[0040] The biological characteristics of the Sal M1P1 of the present invention are as follows: under an electron microscope, Sal M1P1 is composed of a regular hexahedral head with a length of about 67 nm and a tail with a length of 147 nm, and belongs to the family Myocaudatus.

[0041] The infection characteristics of the Sal M1P1 of the present invention are as follows: the incubation period of Sal M1P1 infecting the wild strain of Shewanella algae S.alga is 15 minutes, the lysis period is 5.5 hours, and the phage release amount is 15 PFU / cell.

[0042] The Sal M1P1 of the present invention is insensitive to both 2% and 20% chloroform.

[0043] Experiments have shown that the Sal M1P1 of the present invention can infect not only the wild strain S.alga of Shewanella algae, but also Shewanella upenei 20-23R(T), Vibrio campbellii CAIM 519(T), Vibrio mytiliCAIM 528(T), Vibrio parahaemolyticus NBRC 12711(T) and the Shewanella algae mutant strain S.alga M generated by infecting the wild strain S.alga of Shewanella algae with a single wild strain phage Sal P* of Shewanella algae.

[0044] In another specific embodiment of the present invention, a Shewanella algae phage composition is provided, wherein the composition comprises the Shewanella algae wild strain phage Sal P* and the Shewanella algae mutant strain phage Sal M1P1.

[0045] The titers of the algae Shewanella phage Sal P* and Sal M1P1 of the present invention are both not less than 10 8 PFU / ml.

[0046] When the algae Shewanella phage Sal P* and Sal M1P1 of the present invention are used in combination, the titer ratio of the two is 1:1; the multiplicity of infection MOI is 0.1. Studies have found that when the MOI is 0.1, the growth of the wild strain of algae Shewanella S.alga can be completely inhibited without generating mutants.

[0047] In another specific embodiment of the present invention, there is provided use of the above-mentioned Shewanella algae bacteriophage or bacteriophage composition in the preparation of a Shewanella algae fungicide.

[0048] In another specific embodiment of the present invention, a Shewanella algae fungicide is provided, wherein the Shewanella algae fungicide comprises the Shewanella algae bacteriophage or bacteriophage composition described above.

[0049] In another specific embodiment of the present invention, the Shewanella algae fungicide is in the form of a wettable powder, a water dispersible granule or a water suspension concentrate, preferably a water suspension concentrate.

[0050] In another specific embodiment of the present invention, the Shewanella algae fungicide further comprises an auxiliary material acceptable to the aquaculture industry, and the auxiliary material acceptable to the aquaculture industry is selected from one or more of a dispersant, a stabilizer, a filler and a solvent. There is no special restriction on the source of the auxiliary material acceptable to the aquaculture industry of the present invention, and generally commercially available products can be used.

[0051] Wherein, the dispersant is one or both of sodium tripolyphosphate and sodium pyrophosphate.

[0052] The stabilizer may be selected from one or more of sodium alginate, gelatin, xanthan gum or guar gum.

[0053] The filler can be selected from one or more of chitosan, diatomaceous earth, bentonite, and attapulgite.

[0054] The solvent may be selected from water (preferably deionized water).

[0055] In another specific embodiment of the present invention, there is provided use of the above-mentioned Shewanella algae bacteriophage, bacteriophage composition or Shewanella algae bactericide in controlling Vibrio infection in aquaculture.

[0056] In order to better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0057] In the following example, the formula of the 2216E medium is: 1 g yeast powder, 5 g peptone, 0.01 g ferric orthophosphate, 1000 ml seawater, pH 7.6.

[0058] The 2216E solid culture medium comprises: 1 g yeast powder, 5 g peptone, 0.01 g ferric orthophosphate, 15 g agar, 1000 ml seawater, pH 7.6.

[0059] The 2216E semi-solid culture medium comprises: 1 g yeast powder, 5 g peptone, 0.01 g ferric orthophosphate, 15 g agar, 1000 ml seawater, pH 7.6.

[0060] Example 1 Isolation of wild-type bacteriophage Sal P* from Shewanella algae

[0061] Take a sample of nearshore water, filter it through a 0.22μm sterile filter membrane, add it to the wild strain S.alga of seaweed in the logarithmic growth phase at a volume ratio of 10%, and culture it in a shaking table at 28℃. Take samples on the 1st, 3rd, 5th, and 7th days respectively, filter and sterilize the samples through a 0.22μm sterile filter head, dilute different concentration gradients with SM Buffer, then mix 1ml of the diluted filtrate with 1ml of the wild strain S.alga of seaweed in the logarithmic growth phase, and incubate it in a shaking table at 28℃ for 30min, then pour in the melted pre-cooled 2216E semi-solid at about 48℃, mix and pour on the 2216E solid plate, and shake evenly horizontally until the semi-solid solidifies. Place the semi-solid plate in a 28℃ constant temperature incubator and culture overnight. If plaques appear, it is the phage obtained by preliminary separation.

[0062] Example 2 Purification of wild-type bacteriophage Sal P* from Shewanella algae

[0063] The plaques obtained in Example 1 were soaked in SM Buffer overnight, and then the soaking solution was filtered through a 0.22 μm sterile filter and diluted with SM Buffer in a gradient manner. A double-layer plate was prepared according to the method described in Example 1 to obtain plaques uniformly dispersed on the double-layer plate. The above operation was repeated 3-5 times until the size and morphology of the plaques on the double-layer plate obtained in the last step were consistent. The purified phage double-layer plate was shown in FIG. Figure 1 .

[0064] Example 3 Isolation of Shewanella algae mutant strain S.alga M resistant to wild-type Shewanella algae phage Sal P*

[0065] 100ul of logarithmic phase wild strain S.alga bacterial liquid was mixed with 100ul of bacteriophage liquid and incubated in a 28℃ shaker for 30min, then poured into the melted 2216E semi-solid pre-cooled to about 48℃, mixed and poured on the 2216E solid plate, and shaken evenly horizontally until the semi-solid solidified. The semi-solid plate was cultured in a 28℃ constant temperature incubator overnight. After the bacteria on the plate grew out, a 100ul pipette was used to pick different single colonies (judged whether they were different single colonies by color, shape, size, transparency, etc.), and the three-zone line method was used to purify the colonies. Purification 2-3 times can basically purify single colonies. Pick out a single colony on the plate and place it in a 5ml 2216E liquid test tube. Culture it at 28°C, 150rpm for 2-3 days. Take out 1.4ml of the cultured bacterial liquid and place it in a 1.5ml centrifuge tube. Use the freeze-thaw method to extract bacterial DNA. Use the extracted DNA as a template for PCR amplification and send for testing.

[0066] Example 4 Isolation of Shewanella algae mutant phage Sal M1P1

[0067] The specific implementation method is the same as described in Example 1.

[0068] Example 5 Purification of Shewanella algae mutant phage Sal M1P1

[0069] The specific implementation method is the same as in Example 2. The purified phage double-layer plate is shown in Figure 2 . Phage plaques of uniform size and shape are formed on the plate.

[0070] Example 6 Determination of the titer of wild strain phage Sal P* of Shewanella algae

[0071] The solutions of different phages obtained in the above examples filtered through a 0.22 μm sterile filter were diluted with SM Buffer at different times, mixed with the logarithmic phase wild strain S. alga bacterial solution to make double-layer plates, and the double-layer plates were cultured at 28°C overnight to grow plaques. The plaques on the double-layer plates were counted, and the plates with 30-300 plaques on the plates were selected to calculate the titer. The number of plaques on the plate was converted to the corresponding dilution multiple, which was the titer of the phage. For example, the Sal P* phage solution was diluted 10 -9 There are 100 plaques on the double-layer plate that was poured out later, so the titer of the Sal P* phage solution is 1*10 12 PFU / ml.

[0072] Example 7 Determination of the titer of Shewanella algae mutant phage Sal M1P1

[0073] The specific implementation method of the titer determination of Sal M1P1 is the same as that of Example 6. The titer of Sal M1P1 was determined to be 5*10 9 PFU / ml.

[0074] Example 8 Electron Microscopic Morphological Observation of Shewanella algae Phage Sal P* and Sal M1P1

[0075] The wild strain phage Sal P* of Shewanella algae and the mutant phage Sal M1P1 of Shewanella algae were added to the bacterial solution of the wild strain S.alga of Shewanella algae in the logarithmic growth phase at a ratio of MOI = 0.1, and then placed in a shaker at 28°C and 150rpm for 2-3 days. The co-culture solution was filtered with a 0.22um sterile filter to obtain an enriched phage solution. Then DNase and RNase with a final concentration of 2ng / L were added thereto, and the mixture was gently mixed and allowed to stand at room temperature for 1h. After standing, NaCl with a final concentration of 1M was added to the solution, and it was gently mixed and allowed to stand for 30min. The above solution was centrifuged (8000rpm, 30min) to collect the supernatant, and PEG 8000 with a final concentration of 10% was added to the supernatant solution, and it was placed at 4°C in the dark for 24h. Then the precipitate was collected by centrifugation at 10000g, and the precipitate was resuspended in SM Buffer. Add 7 ml of 1.5 g / ml cesium chloride solution to an ultracentrifuge tube, then add 5 ml of the phage suspension resuspended in SM Buffer, ultra-high speed vacuum centrifuge (200000 x g, 4°C, 8 h), and aspirate the light blue phage band obtained by centrifugation. Use a 30KD ultrafiltration tube to replace the buffer with SM Buffer. The sample is negatively stained with uranyl acetate and used to observe the phage morphology under a transmission electron microscope. The electron microscopic morphology of Sal P* is shown in Figure 3 The electron microscopic morphology of Sal M1P1 is shown in Figure 4 Sal P* is a regular hexahedral head with a diameter of 51nm and a tail length of 331nm. SalM1P1 has a hexahedral head length of 67nm and a tail length of about 147nm. Both belong to the Myoviridae family.

[0076] Example 9 Chloroform sensitivity test of wild strain of Shewanella algae phage Sal P*

[0077] The logarithmic phase wild strain of Shewanella algae S.alga was mixed with a heated and pre-cooled semi-solid culture medium (48°C) to prepare a double-layer plate. Different phage solutions were obtained using the above embodiment to prepare chloroform solutions with volume fractions of 2% and 20%, respectively. The control group was a phage solution without any treatment. After vortexing, each experimental group was allowed to stand at room temperature for 30 minutes, and then centrifuged at 8000rpm. 10μl of the upper aqueous phase was taken and dropped onto the above double-layer plate. The plates were cultured in a constant temperature incubator at 28°C overnight, and the plaque size of the experimental group was observed to see if there was any difference between that of the control group. Chloroform sensitivity test of Sal P* on double-layer plates is shown in Figure 2. Figure 5 There was no difference in the size of plaques formed by chloroform-treated phages and those in the control group, indicating that the phages were insensitive to chloroform and had no lipid structure.

[0078] Example 10 Chloroform sensitivity test of Shewanella algae mutant phage Sal M1P1

[0079] The specific implementation method is the same as in Example 9. The chloroform sensitivity test plate of Sal M1P1 is shown in Figure 6 There was no difference in the size of plaques formed by chloroform-treated phages and those in the control group, indicating that the phages were insensitive to chloroform and had no lipid structure.

[0080] Example 11 Detection of the host range of wild-type Shewanella algae phage Sal P*

[0081] In this experiment, 17 strains of Vibrio that are known and preserved in this laboratory were selected for phage host range detection as listed in Table 1. That is, different Vibrio that have grown to the logarithmic phase were mixed with the pre-cooled 2216E semi-solid (about 48°C) to make a double-layer plate. After the upper semi-solid solidified, 10μl of phage Sal P* filtered through a 0.22μm sterile filter membrane was added dropwise. The plate was placed in a 28°C incubator overnight to observe whether plaques appeared. If so, it indicates that the host can be lysed by phage Sal P*; if not, it indicates that the host cannot be lysed by phage Sal P*. The results of the host range detection of Sal P* are shown in Table 1.

[0082] Example 12 Detection of the host range of Shewanella algae mutant phage Sal M1P1

[0083] The specific implementation method is the same as that of Example 11. The host range detection results of Sal M1P1 are shown in Table 1. Among the detected hosts, Sal M1P1 can lyse a total of six strains of Vibrio including S. alga.

[0084] Example 13 One-step growth curve determination of wild-type Shewanella algae phage Sal P*

[0085] According to the Sal P* phage titer determined in Example 6 and Example 7, when the wild strain of Shewanella algae S.alga grew to the logarithmic phase, the phage Sal P* filtered through a 0.22 μm sterile filter membrane was added at an MOI of 0.01, and incubated on a shaker at 28°C for 30 minutes, then centrifuged at 8000 rpm for 10 minutes, and the bacterial precipitate was resuspended and washed 3 times with fresh 2216E culture medium, and then added with 2216E culture medium and incubated on a shaker at 28°C. Starting from 0h, samples were taken every 15 minutes, and 1 ml of the sample was directly fixed with glutaraldehyde (final concentration 0.5%) to obtain a bacterial sample; 1 ml of the sample was filtered with a 0.22 μm sterile filter head and then fixed with glutaraldehyde (final concentration 0.5%) to obtain a phage sample. After each group of samples was fixed with glutaraldehyde in the dark for 30 minutes, the amount of bacteria or phage was determined by flow cytometry, and the change curve of each parameter over time was plotted. The one-step growth curve of Sal P* is shown in Figure 7 The incubation period of Sal P* lysis of S. alga is 30 minutes, and the lysis period is about 75 minutes.

[0086] Example 14 One-step growth curve determination of Shewanella algae mutant phage Sal M1P1

[0087] The specific implementation method is the same as in Example 13. The one-step growth curve of Sal M1P1 is shown in Figure 8 The incubation period of Sal M1P1 lysing S. alga was 30 minutes, and the lysis period was about 5.5 hours.

[0088] Example 15 Evaluation of bacteriocidal effect of phage cocktail

[0089] According to the titer of wild-type phage Sal P* of Shewanella algae determined in Example 6 and Example 7, three experimental groups were set up, and phage Sal P*, Sal M1P1 and Sal P*+M1P1 were mixed with S. alga at a ratio of MOI=0.1, and then cultured in a shaking incubator at 28°C. The control group was cultured alone with wild-type Shewanella algae. Three parallels were set up for each experimental group. Samples were taken every 1 hour from 0 hours, and samples were taken every 2 hours after 20 hours until 60 hours, and the OD of the bacterial solution was measured. 600 The concentration curve of wild strain S.alga of Shewanella algae was plotted under MOI = 0.1. The bactericidal effect of phage cocktail under MOI = 0.1 is shown in Fig. 9 After adding wild-type phage Sal P* of Shewanella algae for 5 hours, the OD 600 Start to descend from OD 600 =1.134 down to OD 600 =1.005, OD at 34h 600The value was the smallest, which was 0.171, and the bactericidal rate was 95.7%. After 14 hours of addition of the mutant phage Sal M1P1 of Shewanella algae, OD 600 The value slowly decreased, and the lysis time of Sal P* increased compared with the wild-type phage. At 50h, OD 600 The value was the smallest, 0.22, and the bactericidal rate was 95.0%. When the wild-type phage Sal P* and the mutant phage Sal M1P1 were used together, the OD 600 The value is the smallest, which is 0.137, and the bactericidal rate is 97.0%. The combination of two phages can not only lyse the host bacteria faster, but also maintain the OD of the bacterial solution. 600 <0.3 for more than 48 hours.

[0090] Table 1

[0091]

[0092] Note: “+” indicates that the host bacteria is sensitive to the bacteriophage; “-” indicates that the host bacteria is not sensitive to the bacteriophage.

[0093] It should be noted that the above examples are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention is described in detail with reference to the given examples, those skilled in the art may modify or replace the technical solution of the present invention as needed without departing from the spirit and scope of the technical solution of the present invention.

[0094]

[0095]

Claims

1. A phage composition of Shewanella algae having broad-spectrum lytic activity, It is characterized in that The composition contains bacteriophage SalP* and bacteriophage SalM1P1; Among them, the wild strain phage SalP* of Shewanella algae has been sent to the China Center for Type Culture Collection (address: Wuhan University, Luojia Mountain, Wuchang, Wuhan City, Hubei Province), with a preservation date of July 22, 2024 and a preservation number of CCTCC M20241643; The mutant phage Sal M1P1 of Shewanella algae has been sent to the China Center for Type Culture Collection (address: Wuhan University, Luojia Mountain, Wuchang, Wuhan City, Hubei Province), with a preservation date of July 22, 2024 and a preservation number of CCTCC M20241644.

2. The algae Shewanella phage composition according to claim 1, It is characterized in that The titers of the bacteriophages SalP* and SalM1P1 are not less than 10 8 PFU / ml.

3. The Shewanella algae phage composition according to claim 1, It is characterized in that The multiplicity of infection (MOI) was 0.

1.

4. Use of a bacteriophage composition of Shewanella algae with broad-spectrum lytic activity in the preparation of a Shewanella algae fungicide.

5. The use according to claim 5, Features: The bacteriophage composition is used in preparing a bacterial agent for controlling Vibrio infection in aquaculture.

6. A Shewanella algae fungicide, It is characterized in that The Shewanella algae fungicide comprises the Shewanella algae bacteriophage composition.

7. The Shewanella algae fungicide according to claim 7, It is characterized in that The formulation of the Shewanella algae fungicide is wettable powder, water dispersible granules or water suspension.

8. A use of the Shewanella algae fungicide according to claim 7, Features: The algae Shewanella fungicide is used in controlling Vibrio infection in aquaculture.

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