Vibrio parahaemolyticus bacteriophage and application thereof

Abstract

The invention discloses a vibrio parahaemolyticus phage Ph19S9E2 and application thereof, the vibrio parahaemolyticus phage Ph19S9E2 is preserved in the China Center for Type Culture Collection (CCTCC) located in Wuhan University in China on April 15, 2025, and the preservation number is CCTCC NO: M2025789. The vibrio parahaemolyticus phage Ph19S9E2 has the advantages that the vibrio parahaemolyticus phage Ph19S9E2 can be used for preparing the vibrio parahaemolyticus phage Ph19S9E2; the vibrio parahaemolyticus bacteriophage provided by the invention can specifically and effectively split vibrio parahaemolyticus VP19S9E2, and has high-strength host specificity.

Description

Technical Field

[0001] The present invention relates to the field of biomedical technologies, and particularly to a Vibrio parahaemolyticus phage and its applications. Background Art

[0002] Vibrio parahaemolyticus ( Vibrio parahaemolyticus, VP) is a halophilic Gram-negative bacillus and is a pathogenic bacterium causing foodborne diseases, mainly originating from aquatic products such as fish, shrimps, crabs, shellfishes, and seaweeds.

[0003] Currently, the clinical prevention and control of Vibrio parahaemolyticus infections mainly rely on antibiotics and chemical disinfectants, but both have significant drawbacks. The abuse of antibiotics has accelerated the evolution of multi-drug resistant strains, resulting in a simultaneous increase in the risk of treatment failure and public health costs; while the non-specific bactericidal characteristics of chemical disinfectants not only disrupt the microecological balance of water bodies, but their residues may also produce ecological toxicity through bioaccumulation. Under these two-fold challenges, the development of a new prevention and control technology with species specificity and environmental compatibility has become an urgent need for the green and sustainable development of the aquaculture industry.

[0004] In view of this, phage therapy has become a potential strategy to address the challenge of drug resistance due to its precise host recognition ability, targeted lysis characteristics, and ecological safety advantages. Compared with traditional antibiotics, this therapy can not only specifically eliminate target pathogens, but also maintain the homeostasis of the host symbiotic flora.

[0005] Research shows that phage treatment can significantly improve the survival rate of economic species such as fish and shrimps in aquaculture. In addition, in vitro and in vivo tests on aquatic animals such as abalones and oysters further show that phage therapy can effectively control the outbreak of vibriosis.

[0006] Although there is a theoretical risk of horizontal transfer of virulence genes or drug resistance genes mediated by phages, the dual barrier effects of its narrow host specificity and limited resistance mutation frequency make this risk difficult to pose a substantial threat in the application scenario. However, the diversity of existing phage libraries is still insufficient, which may pose certain limitations to its large-scale application. Summary of the Invention

[0007] The present invention provides a Vibrio parahaemolyticus phage that can specifically and effectively lyse Vibrio parahaemolyticus VP19S9E2 and has high-intensity host specificity.

[0008] The technical solution of the present invention is as follows: A Vibrio parahaemolyticus phage ( Vibrio parahaemolyticus phage) Ph19S9E2 was deposited on April 15, 2025 at the China Center for Type Culture Collection (CCTCC) located at Wuhan University, China, with the deposit number CCTCC NO: M 2025789.

[0009] A phage of Vibrio parahaemolyticus was isolated from an aquaculture water sample. By systematically analyzing its biological characteristics, genomic features, and antibacterial effect, this phage was identified as a Podoviridae phage and named Vibrio parahaemolyticus phage Ph19S9E2. The phage Ph19S9E2 of the present invention has a significant inhibitory effect on Vibrio parahaemolyticus VP19S9E2.

[0010] The genomic features of the phage include: the genome size is 51,083 bp, the GC content is 41.52%, and it contains 72 coding DNA sequences (CDS) and 3 tRNAs.

[0011] The 72 coding DNA sequences are divided into a regulation module, a lysis module, a packaging module, a structural module, a DNA metabolism module, a nucleotide metabolism module, a protein synthesis and modification module, an auxiliary metabolic module, a host interaction module, and hypothetical proteins; the lysis module contains an endolysin-encoding gene.

[0012] No virulence and drug resistance genes were detected in the whole genome of the phage Ph19S9E2.

[0013] The phage Ph19S9E2 has good activity in the range of 20 - 60 °C and a pH value of 4 - 11.

[0014] The latent period of the phage Ph19S9E2 is 5 - 15 min, the lysis period is 30 - 60 min, and the average burst size is 40 - 50 PFU / cell.

[0015] The phage Ph19S9E2 has a high specificity for Vibrio parahaemolyticus VP19S9E2.

[0016] The present invention also provides the application of the phage Ph19S9E2 in the preparation of a drug for preventing and treating diseases caused by foodborne Vibrio parahaemolyticus.

[0017] The present invention also provides a phage composition comprising the phage Ph19S9E2 described above.

[0018] The present invention also provides an antibacterial agent comprising the phage Ph19S9E2 or the phage composition described above.

[0019] Preferably, the pH value of the antibacterial agent is 4 - 11.

[0020] In the antibacterial agent, the titer of the phage Ph19S9E2 can reach 10.26 lgPFU / mL.

[0021] The present invention also provides an aquatic animal feed additive comprising the phage Ph19S9E2 described above.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention discovers and isolates a pathogenic Vibrio parahaemolyticus VP19S9E2, and isolates a Vibrio parahaemolyticus phage Ph19S9E2 using the pathogenic Vibrio parahaemolyticus VP19S9E2 as a host. The phage Ph19S9E2 can specifically and effectively inhibit the growth of Vibrio parahaemolyticus VP19S9E2, and no coding sequences related to toxicity, allergen or antibiotic resistance are found in its known functional genes.

[0023] The present invention deepens the understanding of the diversity and evolution mechanism of specific phage families, provides key materials for the research and development of new antibacterial agents, and opens up new ideas for innovatively solving the problem of vibrio infection. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a morphological photograph of the phage Ph19S9E2 on a double-layer agar plate.

[0025] Figure 2 It is a transmission electron microscope photograph of the phage Ph19S9E2.

[0026] Figure 3 It is an effect diagram of the influence of temperature on the titer of the phage Ph19S9E2.

[0027] Figure 4 It is an effect diagram of the influence of pH on the lysis ability of the phage Ph19S9E2.

[0028] Figure 5 It is a one-step growth curve diagram of the phage Ph19S9E2.

[0029] Figure 6 It is an analysis diagram of the antibacterial effect of the phage Ph19S9E2. DETAILED DESCRIPTION OF THE INVENTION

[0030] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be pointed out that the embodiments described below are intended to facilitate the understanding of the present invention and do not have any limiting effect on the present invention.

[0031] If no specific experimental steps or conditions are specified in the examples, the conventional experimental steps or conditions described in the literature in the field can be used. If no manufacturer is specified for the reagents or instruments used, they are all conventional reagent products that can be obtained commercially.

[0032] Example 1 This embodiment provides a bacteriophage, which is named Ph19S9E2. The isolation and purification of the bacteriophage are as follows: (1) Isolation of host bacteria Mackerel from the aquatic product trading market was obtained, and an appropriate amount of tissue samples were cut and placed in a sterile mortar. After fully grinding, 5 mL of sterile saline was added to fully dissolve and mix. After standing for 30 min, 100 μL of supernatant was taken.

[0033] Spread the supernatant on TCBS solid medium and culture at 37℃ for 18 h. Pick a single colony and streak it on the same selective medium for purification, repeat 3 times. Inoculate a single colony with consistent morphology into 3% sodium chloride alkaline peptone water medium, culture at 37℃ until turbidity, pipette 750 μL of bacterial solution and 750 μL of 50% glycerol into a sterile cryopreservation tube, mix well and store at -80℃.

[0034] The strain was identified as Vibrio parahaemolyticus by time-of-flight mass spectrometry, followed by whole-genome sequencing. After comparison with the NCBI database, it was again verified to be Vibrio parahaemolyticus and named Vibrio parahaemolyticus VP19S9E2, as the host bacteria of bacteriophage Ph19S9E2. The public accession number of the genome of Vibrio parahaemolyticus VP19S9E2 on the NCBI official website is JBOEHL000000000.

[0035] (2) Expansion of host bacteria The host bacteria can be inoculated in single colony inoculation and liquid inoculation. Single colony inoculation means picking a single colony from a streaked plate on a clean bench and placing it in the culture medium; liquid inoculation means placing a 10% inoculation concentration of 10 8 -10 9 CFU / mL bacterial solution was added to the culture medium.

[0036] The culture medium used for expansion culture was 3% sodium chloride alkaline peptone water culture medium, and the culture conditions were: temperature of 37°C and rotation speed of 180 rpm.

[0037] (3) Phage screening Using the multi - locus sampling method, a total of 24 water samples were collected from aquaculture areas and surrounding rivers (6 market water samples and 18 river water samples). By using the method of mixed enrichment of bacterial liquid - water sample, about 20 mL of pretreated water sample was placed in a 50 mL centrifuge tube, 20 mL of 3% sodium chloride alkaline peptone water liquid medium was added, and 2 mL of the host bacteria with a content of 10 8 -10 9 CFU / mL was added, and the mixture was cultured in a shaker at 37℃ and 180 rpm for 12 - 24 h.

[0038] The liquid after enrichment culture was extracted, centrifuged at 10,000 rpm for 10 min, and the supernatant was retained. Then the supernatant was filtered through a 0.22 μm filter membrane, and the obtained filtrate was the original solution of Vibrio parahaemolyticus phage. The double - layer plate method was used to observe whether plaque appeared to judge whether phage was isolated.

[0039] The phage screened in this example was named Ph19S9E2.

[0040] (4)Purification of phage On the plate with formed plaques, a single plaque (together with the bottom medium) was picked up with a pipette tip and transferred to a 2 mL centrifuge tube containing 1 mL of SM buffer, and cultured overnight at 4℃. Centrifuged at 12,000 rpm for 5 min, filtered through a 0.22 µm microporous filter membrane, and the filtrate was collected. The filtrate was serially diluted 10 - fold and then cultured by the double - layer plate method. Repeat the above steps 5 - 7 times until the plaque morphology and size on the plate are consistent, indicating that the purification is completed. The purified plaque diagram is as Figure 1 shown. The edge of the plaque is clear, neat and transparent, and its diameter is about 1 - 2 mm.

[0041] Example 2 In this example, transmission electron microscopy imaging was performed on the phage (phage Ph19S9E2) screened in Example 1.

[0042] (1)Observation of phage morphology by transmission electron microscopy Take 10 µL of phage concentrate, drop it onto a copper grid. After adsorption for 1 min, gently suck off the excess liquid with filter paper. Subsequently, 1 drop of 2% phosphotungstic acid was added for staining. After staining for 1 min, the excess staining solution was again sucked off with filter paper. After the sample was naturally dried, the sample was observed using a Hitachi H7650 transmission electron microscope under the condition of 80 kV to obtain a high - resolution image of phage particles. As Figure 2 shown, the head of this phage shows a standard hexagonal morphology, with a diameter of about 66.70 nm and a tail length of about 12.40 nm. The overall morphological characteristics conform to the typical characteristics of the viruses in the family Podoviridae of the order Caudovirales.

[0043] Example 3 In this example, the optimal multiplicity of infection (MOI) of the phage (phage Ph19S9E2) obtained by screening in Example 1 was determined.

[0044] (1) Amplification culture of phage Take 200 µL of the revived phage solution, mix it with an equal volume of the host bacteria with a content of 10 8 -10 9 CFU / mL, let it stand and adsorb at 28°C for 12 min, then centrifuge at 10,000 g for 2 min, discard the supernatant, resuspend the precipitate with 1 mL of SM buffer, centrifuge at 10,000 g for 2 min, discard the supernatant, and resuspend the precipitate again with 1 mL of SM buffer.

[0045] Take a 50 mL centrifuge tube, add 10 mL of 3% sodium chloride alkaline peptone water medium and the above 1 mL of SM buffer resuspension to it, place the centrifuge tube in a shaker at 37°C and 180 rpm and shake and culture for 3 h until the culture solution becomes clear. Subsequently, use a high-speed refrigerated centrifuge to centrifuge at 4°C and 12,000 rpm for 10 min. Filter the supernatant through a 0.22 µm filter membrane to obtain a phage enrichment solution.

[0046] (2) Determination of the MOI of this phage against Vibrio parahaemolyticus Mix and culture the phage and the host bacteria at different MOI values (100, 10, 1, 0.1, 0.01, 0.001), and use the double-layer plate method to determine the phage titer. The MOI value that produces the highest phage titer is the optimal multiplicity of infection. During the experiment, three replicates are set for each MOI value to ensure the reliability of the experimental data.

[0047] Table 1 Determination results of the optimal multiplicity of infection of phage against Vibrio parahaemolyticus

[0048] From the determination results in Table 1, it can be seen that the phage has the highest titer against Vibrio parahaemolyticus when the MOI is 10, which can reach 10.26 lgPFU / mL.

[0049] Example 4 In this example, the thermal stability, pH stability and one-step growth curve of the phage (phage Ph19S9E2) obtained by screening in Example 1 were determined.

[0050] (1) Determination of phage thermal stability Samples were respectively placed in a water bath environment at 20, 30, 40, 50, 60, and 70 °C for 60 min. 1 mL of fresh phage solution with a known titer was taken into a 1.5 mL centrifuge tube and treated in a water bath at 20, 30, 40, 50, 60, and 70 °C for 60 min. Three replicate experiments were set under each temperature condition to ensure the reliability of the data. After the treatment time ended, the samples were quickly taken out and immediately placed in an ice bath for cooling to terminate the heat treatment process. Subsequently, the samples were appropriately diluted for subsequent determination. Subsequently, the phage titer was measured every 30 min to monitor the effect of heat treatment on the phage titer and its change over time.

[0051] As Figure 3 shown, phage Ph19S9E2 maintained good activity in the temperature range of 20 - 50 °C. Figure 3 The broken lines at 20 °C, 30 °C, 40 °C, and 50 °C in [the figure] were basically coincident, and the phage titer of Ph19S9E2 remained basically unchanged within 60 min at 20 - 50 °C. However, when the temperature rose to 60 °C, its titer gradually decreased with the extension of time and was completely inactivated after incubation at 70 °C for 30 min. This indicates that phage Ph19S9E2 has a high tolerance to normal temperature but is intolerant to high temperature.

[0052] (2)Determination of phage pH stability Using hydrochloric acid and sodium hydroxide solutions, the pH values of 3% sodium chloride alkaline peptone water medium were adjusted to 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, and 13 respectively, and then autoclaved. 100 μL of phage solution was pipetted and added to 900 μL of liquid medium with different pH values to fully mix the phage solution and the medium. The mixed samples were placed in a constant temperature environment at 28 °C. After reacting for 2 h, the phage titer in each tube was measured to evaluate the effect of different pH values on the phage titer. To ensure the reliability of the experimental data, three parallel samples were set for each pH value for replicate experiments.

[0053] As Figure 4 shown, phage Ph19S9E2 was stable in activity in the environment of 4 ≤ pH ≤ 11. When the pH was 6, the phage had the highest activity, while it lost activity when pH < 3 and pH > 12. This indicates that this phage has a large acid-base tolerance range and has high activity between pH values of 4 and 11.

[0054] (3)Determination of phage one-step growth curve Mix the phage and the host bacteria according to the ratio of the optimal multiplicity of infection, let them stand and adsorb at 28 °C for 12 min, then centrifuge at 10,000 g for 2 min, discard the supernatant. Resuspend the precipitate with 1 mL of SM buffer, centrifuge at 10,000 g for 2 min, discard the supernatant, resuspend the precipitate again with 1 mL of SM buffer, dilute it 10-5 times to 10 mL, and culture it with shaking at 28 °C and 220 rpm. Measure the titer every 10 min. Repeat 3 times for each time point. Finally, use time as the abscissa and phage titer as the ordinate to plot the one-step growth curve of the phage, and determine the latent period, burst period, stationary period of the phage and calculate the burst size.

[0055] Burst size (PFU / cell) = phage titer at the end of lysis / initial concentration of host bacteria solution (1) As Figure 5 shown, the one-step growth curve of phage Ph19S9E2 shows that 0-10 min is the latent period of phage Ph19S9E2, 10-50 min the phage enters the lysis period, and after 50 min the curve flattens out, indicating entry into the stationary period. Calculate the burst size to be approximately 44.70 PFU / cell according to formula (1).

[0056] Example 5 In this example, the host range of the phage (phage Ph19S9E2) screened in Example 1 was determined.

[0057] Use the spot test method to determine the host range of the phage. Take 2 mL of LB semi-solid medium, mix it well with 200 μL of host bacteria in the logarithmic growth phase, and quickly pour it onto the LB solid medium. After it solidifies, add 5 μL of phage solution dropwise, and then place the culture dish in an incubator at 37 °C for 6-12 h to observe whether a lysis zone is formed.

[0058] The host range was determined for 40 strains. These host bacteria include Gram-negative and Gram-positive species. The infection results of this phage on different host bacteria are shown in Table 2.

[0059] Table 2 Host range of phage Ph19S9E2

[0060] From the spot test results shown in Table 2, it can be seen that the phage screened in this application can only infect VP19S9E2, indicating that phage Ph19S9E2 has high specificity for Vibrio parahaemolyticus VP19S9E2. This characteristic is similar to that of phages reported in other studies, and the specificity may be related to the phage-host interaction mechanism.

[0061] Example 6 In this example, the whole genome sequencing and phylogenetic analysis of the phage (phage Ph19S9E2) screened in Example 1 were carried out.

[0062] (1)Extraction and sequencing assembly of phage genome After enriching the phage, it was sent to Wuhan Bena Technology Co., Ltd. for genome extraction and whole genome sequencing. The original sequencing data of the host bacteria and phage were uploaded to the bioinformatics platform, and the bowtie2 software was used to build an index and remove the host bacteria. The sequences obtained after removing the host bacteria were assembled using the Spades software for second-generation assembly and Unicycler v0.5.0 for third-generation assembly and hybrid assembly.

[0063] (2)Whole genome analysis and annotation of phage The nucleotide sequence of the phage was analyzed by nucleotide BLAST search in the National Center for Biotechnology Information (NCBI) database. The complete genome was automatically annotated by Prokka and RAST. Functional annotation was performed again by BLASTp, and compared with the non-redundant protein database of NCBI. The Virulence Factor Database (VFDB) was used to predict whether the phage contained virulence genes, and the Comprehensive Antibiotic Resistance Database (CARD) was used to retrieve and predict whether the phage contained resistance genes. The tRNAscan-SE program was used to predict tRNA. Genes were visualized by the Easyfig 2.2.5 tool to compare the phage genome.

[0064] (3)Phylogenetic tree analysis of phage Sequence alignment analysis of the whole genome sequence of the phage was carried out by BLASTn of NCBI, and the complete genomes of the top 5 phages with high homology were downloaded. The kSNP3.1.2 software was used for phylogenetic analysis, and an appropriate Kmer value was selected. The maximum likelihood method was used to analyze the single nucleotide polymorphism (SNP) of the genome.

[0065] The complete genome sequence of bacteriophage Ph19S9E2 is 51,083 bp long, with a GC content of 41.52%. A total of 72 CDSs were predicted using RAST and Prokka, among which 25 were known phage functional genes, and the remaining 47 were predicted as hypothetical proteins, accounting for approximately 65.28%. The 72 CDSs were classified into 10 different functional modules through functional annotation, including a regulation module, a lysis module, a packaging module, a structural module, a DNA metabolism module, a nucleotide metabolism module, a protein synthesis and modification module, an auxiliary metabolic module, a host interaction module, and hypothetical proteins.

[0066] According to the results of functional annotation, the known regulation module has CDS5 and CDS7, which encode proteins involved in viral DNA packaging and gene expression regulation, respectively; the lysis module is composed of CDS6, which encodes endolysin responsible for degrading the host cell wall; in the packaging module, CDS11 encodes a protein related to viral DNA packaging; the structural module contains CDS13, CDS14, CDS16, CDS19, CDS20, CDS21, and CDS26, and the proteins encoded by these genes are important components of the phage structure; the DNA metabolism module includes CDS29, CDS34, CDS38, CDS40, and CDS44, which encode enzymes involved in viral DNA synthesis, repair, and metabolism; the nucleotide metabolism module consists of CDS31, CDS32, and CDS33, which encode proteins involved in nucleotide synthesis; the protein synthesis and modification module contains CDS51, CDS52, and CDS54, which encode enzymes involved in protein synthesis and modification; the auxiliary metabolic module includes CDS55 and CDS57, which encode enzymes involved in amino acid and nitrogen metabolism; the host interaction module is composed of CDS60, which encodes a protein that interacts with the host cell and may affect the host immune response and phage infection efficiency. In addition, no rRNA was detected, but 3 encoded tRNAs (tRNA carrying proline, tRNA for isoleucine, and tRNA for tryptophan) were found. Finally, based on the alignment analysis of the VFDB and CARD databases, no virulence genes and drug resistance genes were detected in the Ph19S9E2 genome.

[0067] According to the BLASTn alignment analysis, no phage with 100% homology to the genome of phage Ph19S9E2 was found in the existing database, but its functional modules showed certain similarities to other phages. There were nucleotide sequence similarities with Vibrio phages vB_VpP_BA6 (GenBank accession number: MK483107), vB_ValP_IME234 (GenBank accession number: MW748992), vB_ValP_IME271 (GenBank accession number: MF431726), vB_ValC_WD615 (GenBank accession number: OR908438), and VPp1 (GenBank accession number: KJ936628). Among them, the highest homology with vB_VpP_BA6 (GenBank accession number: MK483107) was 97.03%, and the coverage rate was 92.00%.

[0068] By comparing and analyzing the whole genome sequences of phages through BLASTn, 5 phages with high homology were selected to construct a phylogenetic tree. The results of phylogenetic tree analysis based on the whole genome comparison showed that phage Ph19S9E2 and the Podoviridae phage vB_VpP_BA6 were on the same evolutionary branch, had a relatively close genetic relationship, and had a common evolutionary origin. Phage Ph19S9E2 should belong to the Podoviridae phage.

[0069] Example 7 In this example, the phage (phage Ph19S9E2) screened in Example 1 was used to conduct a host bacteria growth inhibition test.

[0070] Take 200 µL of phage and 200 µL of host bacteria and mix and culture them at different MOIs of 0.001, 0.01, 0.1, 1, 10, and 100. Use a real-time microbial growth curve analyzer to measure the absorbance value at OD 600 every 10 min, and draw a curve of the change in absorbance value after culturing at 37°C for 12 h. Each MOI value was paralleled in three groups of experiments, and the same amount of host bacteria VP19S9E2 was used as a positive control.

[0071] It can be seen from Figure 6 that phage Ph19S9E2 has an obvious inhibitory effect on Vibrio parahaemolyticus VP19S9E2, and the inhibitory effect of phage Ph19S9E2 on host bacteria increases with the increase of the MOI value. Vibrio parahaemolyticus VP19S9E2 reached the stationary phase after 10 h of culture. After adding the phage, at high MOI values (0.1 - 100), the growth was inhibited within 6 h, and the exponential phase was observed after 6 h, OD 600The value remained at a lower level during this period compared with the control group, indicating that the high MOI value is a key factor affecting the phage in this study and can more effectively lyse the host bacteria. In addition, it was observed from the figure that when the MOI value was 0.01 - 100, although the number of host bacteria increased at the initial stage of infection, with the reproduction of the phage, the number of bacteria began to decline after a period of time. Subsequently, due to the emergence and reproduction of resistant bacterial subpopulations, the bacterial concentration began to rise again. Compared with the control group, even at a low MOI value (0.001), the phage Ph19S9E2 still had a certain inhibitory effect on the growth of the host bacteria VP19S9E2.

[0072] In summary, a Myoviridae phage Ph19S9E2 was isolated from the aquaculture water of aquatic products in this application. This phage can specifically lyse Vibrio parahaemolyticus VP19S9E2, providing a safer and more efficient solution to the problem of Vibrio parahaemolyticus infection in aquaculture.

[0073] The phage Ph19S9E2 was deposited on April 15, 2025, at the China Center for Type Culture Collection (CCTCC), Wuhan University, China, with the deposit number CCTCC NO: M 2025789, and the whole genome accession number in GenBank on the NCBI official website is PV399855.

[0074] The above embodiments have described in detail the technical solutions and beneficial effects of the present invention. It should be understood that the above are only specific embodiments of the present invention and are not used to limit the present invention. Any modifications, supplements, equivalent replacements, etc. made within the scope of the principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A Vibrio parahaemolyticus phage ( Vibrio parahaemolyticus phage) Ph19S9E2, characterized in that It was deposited on April 15, 2025 at the China Center for Type Culture Collection, Wuhan University, China, with the deposit number CCTCC NO: M 2025789.

2. The Vibrio parahaemolyticus phage Ph19S9E2 according to claim 1, characterized in that, Its genome size is 51,083 bp, the GC content is 41.52%, and it contains 72 coding DNA sequences and 3 tRNAs.

3. The Vibrio parahaemolyticus phage Ph19S9E2 according to claim 1, wherein The 72 coding DNA sequences are divided into regulatory modules, lysis modules, packaging modules, structural modules, DNA metabolism modules, nucleotide metabolism modules, protein synthesis and modification modules, auxiliary metabolism modules, host interaction modules, and hypothetical proteins; the lysis module contains an endolysin-encoding gene.

4. Use of the Vibrio parahaemolyticus phage Ph19S9E2 according to any one of claims 1-3 in the preparation of a drug for preventing or treating diseases caused by foodborne Vibrio parahaemolyticus.

5. A bacteriophage composition, characterized in that, Comprising the Vibrio parahaemolyticus phage Ph19S9E2 according to any one of claims 1-3.

6. An antibacterial agent, characterized in that, Comprising the Vibrio parahaemolyticus phage Ph19S9E2 according to any one of claims 1-3 or the phage composition according to claim 5.

7. The antibacterial agent according to claim 6, characterized in that, The pH value of the antibacterial agent is 4-11.

8. An aquatic animal feed additive, characterized in that, Comprising the Vibrio parahaemolyticus phage Ph19S9E2 according to any one of claims 1-3.

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