125 results about "Edwardsiella tarda" patented technology

The invention provides bacillus velezensis and application of the bacillus velezensis as an aquatic pathogenic bacteria inhibitor. The bacillus velezensis is separated from the intestinal canal of healthy tilapia, and the preservation number of the bacterial strain is GDMCC No. 60344. The bacillus velezensis has a broad-spectrum antagonistic aquatic common pathogenic bacteria function, and has theadvantages that the growth of the pathogenic bacteria, such as streptococcus agalactiae, streptococcus iniae,nocardia seriolea, aeromonas hydrophila, aeromonas schubertii and edwardsiella tarda, canbe effectively inhibited, the use is safe, no residue is generated, reducing the usage amount and the residual amount of chemical drugs in aquaculture is facilitated, the production cost is reduced, and the practicality is strong.

The invention discloses a bacillus amyloliquefaciens strain as well as a preparation method and application of a strain powder preparation of the bacillus amyloliquefaciens strain, and belongs to the technical field of microorganisms. The bacillus amyloliquefaciens JSSW-LA, which is obtained through screening, is preserved in China Center for Type Culture Collection with preservation number of CCTCC NO: M2015602. The strain powder preparation of the bacillus amyloliquefaciens, which is prepared through freeze-dried culture activation, fermentation culture and strain powder preparation, is applicable to an additive of fishery breeding feed or a water quality improver of aquaculture; the bacillus amyloliquefaciens JSSW-LA provided by the invention is capable of effectively inhibiting the growth of A.sobria, A.hydrophila, A.caviae, aeromonas veronii and edwardsiella tarda, and an inhibitory effect on the A.sobria, A.hydrophila and A.caviae is more excellent than that on other pathogenic bacteria. Therefore, the JSSW-LA strain powder, applied to aquaculture, is capable of effectively preventing and controlling diseases in aquaculture animals caused by pathogenic bacteria, in particular bacterial bleeding disease, so as to protect the healthy growth of aquatic animals.

The invention relates to antisepsis and anti-inflammation medicaments, and particularly relates to high-content liquid povidone-iodine. The liquid povidone-iodine is prepared from the following raw materials in percentage by weight: 5.2-12.24 percent of iodine, 10-24 percent of polyvinylpyrrolidone, 2-4.8 percent of potassium iodide, 0.1-0.24 percent of potassium iodate, 15-36 percent of ethanol and the balance of water. The high-content liquid povidone-iodine is a reddish brown viscous liquid, is easily dissolved in water, has stable performance, strong sterilization efficacy and no irritation, is suitable for sterilization of operating parts and skin-mucosa or sterilization of aquatic water, can be used for preventing and treating bacteriosis of aquatic animals caused by vibrio, aeromonas hydrophila, edwardsiella tarda and the like and sterilizing the environment of livestock and poultry housings, plays a role in killing multiple bacteria, spores, viruses, fungi and the like, thus being a good iodine containing medical bactericide and epidemic prevention sanitizer.

The invention relates to a marker-free gene deletion attenuated mutant strain of an Edwardsiella tarda wild strain. The marker-free gene deletion attenuated mutant strain is an attenuated live vaccine of an Edwardsiella tarda virulent strain, which deletes the chorismic acid synthase gene aroC of the Edwardsiella tarda virulent strain, three types of secretion system response element genes of eseB, escA, eseC and eseD and an endogenous plasmid, preferably, the Edwardsiella tarda virulent strain is an Edwardsiella tarda virulent strain EIB202 with the preservation number of CCTCC No:M208068; the endogenous plasmid is a plasmid of pEIB202; and the marker-free gene deletion attenuated mutant strain of the Edwardsiella tarda virulent strain is an attenuated strain WED with the preservation number of CCTCC No:M2010278. The invention also provides relevant preparations and application of the marker-free gene deletion attenuated mutant strain. The attenuated mutant strain or relevant preparations eliminate the potential environment and safety risk of products existing in the traditional attenuated live vaccines generally and is a safe, effective and economic vaccine aiming at Edwardsiella tarda diseases of cultured fishes.

A safe and effective live vaccine against Edwardsiella tarda in fish was created through the induction of rifampicin resistance in a native Edwardsiella tarda isolate. Single immersion exposure or injection of fish stimulated acquired immunity against virulent E. tarda infection.

The invention relates to a flounders quintuplet inactivated vaccine and a preparation method thereof. The main constituents of the vaccine are mixed by the inactivated bacteria of five bacteria such as the vibrio anguillarum, turbot vibrio, the vibro harveyi, the algae dissolving glue vibrio and the edwardsiella tarda. The preparation method comprises the steps of: respectively preparing the five bacteria into 109-1010cfu / mL of vibrio suspension liquid, inactivating the vibrio suspension liquid by formalin, performing the isovolumetric mixing according to the proportion of 1:1:1:1:1 to prepare the flounders quintuplet inactivated vaccine raw liquid, and evenly mixing the flounders quintuplet inactivated vaccine raw liquid with the 15-35mg / mL astragalus polysaccharides adjuvant raw liquid according to the proportion of 1:1. The flounders quintuplet inactivated vaccine is multiple in immunity effects, can be used for effectively preventing the infection of the five bacterial pathogenic bacteria after being vaccinated for once, and provides a basis for the development of the marine fish multi-germinal inactivated vaccine.

The invention discloses a gene chip for detecting ten types of pathogenic bacteria in sea areas. The gene chip comprises a solid phase slide on which a quality control probe and a detection probe are arranged, wherein the nucleotide sequence components of the detection probe are shown in SEQ ID NO.1-SEQ ID NO.27. The gene chip is capable of simultaneously detecting enterobacter cloacae, edwardsiella tarda, streptococcus faecalis, vibrio fortis, vibrio harveyi, vibrio parahaemolyticus, vibrio splendidus, vibrio vulnificus, vibrio anguillarum and shewanella smarisflavi just in the presence of DNA (deoxyribose Nucleic Acid) without need of live bacteria. The gene chip has remarkable advantages of high throughput, parallelism, miniaturization, automation, rapidness, sensitiveness, quantification, small use amount, and the like.

The invention relates to a gene chip in the detection of aquatic pathogenic microorganism, a preparation method and applications thereof in the detection of aquatic pathogenic microorganism. A conserved sequence selecting from a target pathogenic microorganism gene is fixed on a solid-phase carrier as an oligonucleotide probe, in the proper hybridization condition, a marked sample to be detected is added for reaction, and the corresponding aquatic pathogenic microorganism can be identified according to a probe display signal on the gene chip. The gene chip can fast detect the aquatic pathogenic microorganism such as aeromonas hydrophila, edwardsiella tarda, staphylococcus aureus, vibrio parahaemolyticus, listeria monocytogenes, salmonella typhimurium, shigella and the like, thus being high in detection sensitivity, and strong in specificity and greatly shortening the detection period.

A colloidal gold immunochromatographic test strip for rapid detection of Edwardsiella tarda, the invention relates to a method of using nano-colloidal gold particle-labeled antibody technology and double-antibody sandwich immunochromatography to detect antigen patterns, and prepared a colloid of Edwardsiella tarda Gold immunochromatographic test strips. A colloidal gold immunochromatographic detection test strip for Edwardsiella tarda and its preparation method and application are provided. The test strip contains sample pads, gold standard pads, nitrocellulose membranes with detection line and quality control line antibodies, absorbent pads, and bottom plates. The sample pads, gold standard pads, nitrocellulose membranes, and absorbent pads are sequentially overlapped and connected. Assembled by pasting on the bottom plate. The detection application of the test strip is simple in operation, good in specificity, high in sensitivity, convenient and fast, does not require special equipment and professional training, and the results are clear and easy to distinguish and easy to promote. It is suitable for detection of infection and contamination of Edwardsiella tarda.

The invention belongs to the technical field of microorganisms and discloses a preparation method and application of a compound microbial substrate modifier with an aquatic pathogen antagonistic characteristic. Two strains namely bacillus subtilis AB-90008-15 and lactobacillus gasseri 88 are provided, and the compound microbial substrate modifier is obtained by strain activation, fermentation culture, centrifugal strain collection and vacuum drying and grinding. The compound microbial substrate modifier has an antagonistic action on aquatic pathogens such as aeromonas hydrophila, aeromonas sobria, aeromonas veronii, aeromonas caviae, Edwardsiella tarda, listonella anguillarum, vibrio parahaemolyticus and vibrio alginolyticus and is capable of degrading carbonaceous organics and nitrogenousorganics in pond sediment, promoting sediment mineralization, reducing contents of total nitrogen, total phosphorus, nitrite, ammonia nitrogen and COD of aquaculture water, promoting virtuous cycle of waternutrients, preventing accumulation of toxic and harmful substances and improving an aquaculture substrate ecological environment.

The invention relates to the field of gene engineering and immunology, in particular to a method for constructing and applying a cross-protective vaccine of Vibrio harveyi and Edwardsiella tarda, and an antigen expression vector thereof. The cross-protective vaccine has a base sequence in a sequence table SEQ ID No.1, and is constructed by the following steps: constructing plasmids pPT6 and pT6VH; and on the basis, constructing a plasmid pT6VH18 containing the antigen of the cross-protective vaccine of Vibrio harveyi and Edwardsiella tarda. The pT6VH18 is converted into colibacillus to be cultured under a conventional condition so as to obtain the protective vaccine. The vaccine not only has cross-protection effect, but also does not need any purifying process.

The invention relates to an edwardsiella tarda rapid detection test paper which is a colloidal gold immunochromatography detection test paper. An edwardsiella tarda colloidal gold labeled antibody is adsorbed on a combined pad of the colloidal gold immunochromatography detection test paper, a detection line and a quality control line are arranged on an analyzing film of the colloidal gold immunochromatography detection test paper, an edwardsiella tarda antibody coats the detection line, and a second antibody coats the quality control line wherein the immunogen of the second antibody is the same as that of edwardsiella tarda antibody. The invention also provides a method for rapidly detecting edwardsiella tarda and application of the edwardsiella tarda rapid detection test paper in detecting the edwardsiella tarda. The edwardsiella tarda rapid detection test paper can conveniently, rapidly, sensitively and accurately detect the edwardsiella tarda to control the spread of edwardsiella tarda diseases in the early days, has an important significance in controlling the edwardsiella tarda diseases in aquaculture and is suitable for large-scale generalization and application.

The invention discloses eel aeromonas hydrophila and edwardsiella tarda bigeminal recombinant protein and a preparation method thereof. The bigeminal recombinant protein disclosed by the invention comprises an aeromonas hydrophila type II pore protein membrane outer part and an edwardsiella tarda ompS2 membrane outer part which are connected together, and the amino acid sequence of the bigeminal recombinant protein is as shown by SEQ ID NO1. According to the preparation method disclosed by the invention, the aeromonas hydrophila type II pore protein membrane outer part and the edwardsiella tarda ompS2 membrane outer part are connected together through a genetic engineering means to construct the bigeminal recombinant protein, and the bigeminal recombinant protein can prevent inflections of aeromonas hydrophila and edwardsiella tarda at the same time after being used for immunizing eels, and has a better immune effect compared with immunization with single outer membrane protein. The bigeminal recombinant protein disclosed by the invention can obtain an immune effect on a variety of pathogenic bacteria through only once injection on a fish body, so that injuries to the fish body are reduced, and immunization steps are simplified; the preparation method of the bigeminal recombinant protein is suitable for industrial production.

The invention relates to triple oral vaccine for cultivating marine fishes. The triple oral vaccine is prepared by mixing pharmaceutical starch, maltodextrin, vibrio parahaemolyticus broth with the concentration of 1*1012cfu, vibrio alginolyticus broth with the concentration of 1*1012cfu and edwardsiella tarda broth with the concentration of 1*1012cfu in the ratio of 3 to 1 to 0.35 to 0.35 to 0.35 according to the unit mode being g:g:mL:mL:mL. The invention relates to a preparation method of the triple oral vaccine, comprising the following steps of: (1) inactivating; (2) preparing pellets; (3) preparing an enteric coated layer lagging coating; and (4) coating phagostimulant in a spraying way. The invention relates to a use method of the triple oral vaccine, wherein the use method comprises the following steps of: (1) firstly feeding and (2) intentinonally feeding. According to the preparation method provided by the invention, the vibrio parahaemolyticus broth, the vibrio alginolyticus broth and the edwardsiella tarda broth trigeminy oral vaccine can be prepared. A feeding and vaccinating method is used, so that the triple oral vaccine is ideal in immune effect, and small in workload, thereby being suitable for vaccination on a large scale. Meanwhile, the triple oral vaccine provided by the invention adopts a functional coating material, so that the vaccine can not be digested within the gastric juice, and the vaccine can be quickly released within the intestinal tract; and therefore, the immune response can be generated, and the high-efficiency immune effect can be obtained.

The invention discloses a bacterial strain capable of resisting various aquaculture pathogenic bacteria and application thereof. The antagonistic bacterium is Bacillus amyloliquefaciens InAD-160, andthe microbial collection number is CGMCC No.14030. The Bacillus amyloliquefaciens InAD-160 is obtained by separating deep seawater of the Indian Ocean, can inhibit growth of various aquaculture pathogenic bacteria like Edwardsiella tarda, Aeromonas hydrophila, Shewanella putrefaciens and Vibrio vulnificus and can be used for preventing and controlling aquaculture diseases caused by the same. The Bacillus amyloliquefaciens InAD-160 obtained from deep sea is a biological prevention and control potential strain which is high in prevention and control efficiency and wide in prevention and controlrange and has great application and development prospect.

The invention relates to the field of immunology, and specifically relates to an Edwardsiella tarda subunit vaccine and a preparation method thereof. The protein gene of the vaccine has a base sequence shown in SEQ ID No.1 in a sequence table, and the vaccine protein coded by the protein gene has an amino acid sequence as shown in SEQ ID No.2 in the sequence table. The subunit vaccine provided by the invention is mixed with an oil emulsion adjuvant, and then capable of effectively exciting the generation of specific antibodies after immunizing the fish through intraperitoneal injection; the Edwardsiella tarda subunit vaccine is capable of efficiently improving the ability of resisting the infection of the Edwardsiella tarda of the immune fish and thus can be applied to controlling the Edwardsiella tarda of the fish.

The invention discloses a traditional Chinese medicinal recipe for inhibiting Edwardsiella tarda. The recipe is characterized by comprising coptis chinensis franch, fructus schisandrae chinensis, catechu, folium artemisiae argyi, aluminis usti, galla chinensis, fructus mume, siegesbeckia pubescens mak, fructus carpesii, chaenomeles speciosa, reynoutria japonica slice, herba violae, senecio scandens, myrrha, herba houttuyniae, folium perillae, solanum nigrum, fructus rubi, flos caryophyllata, radix clematidis and cortex moutan radicis, wherein a recipe which is formed by mixing the folium artemisiae argyi, the catechu, the fructus schisandrae chinensis and the coptis chinensis franch according to the mass ratio of 4:1:2:1 has an optimum antibacterial effect. The recipe has the advantages of naturality, no toxity and residues, no tolerance and low price.

The invention relates to the field of molecular biology and immunology and particularly discloses an Edwardsiella tarda recombinant subunit vaccine as well as a preparation method and application thereof. The vaccine has a base sequence in a sequence table SEQ ID No.1. The preparation method of the Edwardsiella tarda recombinant subunit vaccine comprises the following steps of constructing a vaccine antigen expression plasmid pETXV21, converting the vaccine antigen expression plasmid pETXV21 into escherichia coli BL21 (DE3), recovering a recombinant protein after induced expression, mixing the recombinant protein with a strain B187, and dissolving the mixture in PBS (Phosphate Buffer Saline) to obtain a vaccine mixed liquor which has the function of immune protection to Edwardsiella tarda. The vaccine mixed liquor is intraperitoneally injected to fishes to achieve the purpose of immune protection.

The invention relates to an aquiculture animal disease prevention and control technology, in particular to an Edwardsiella tarda attenuated strain for preventing and controlling Edwardsiella tarda infection and application thereof. An Edwardsiella tarda mutant strain is MZLLSE40aroA which is preserved in CGMCC and has the preservation number: CGMCC No.2886 and the Edwardsiella tarda mutant strain is MZL LSE40 aroAesrB which is preserved in CGMCC and has a preservation number: CGMCCNo.2887. Bacterial cells of 106-109cfu / mL of Edwardsiella tarda strain MZL LSE40aroA or the Edwardsiella tarda strain MZL LSE40 aroAesrB and sterile phosphoric buffer salt solution are mixed as an attenuated live vaccine for preventing and controlling Edwardsiella tarda disease of culture fish. The strain has intraframe large-scale deletion of virulence related genes and nutrition metabolization related genes and non-recoverable virulence, does not contain a foreign gene segment and an antibiotics resistance marker and is safe for the environment and animals.

The invention relates to the field of molecular vaccinology, in particular to two Edwardsiella tarda recombinant protein vaccines, and a preparation method thereof. The antigens of the vaccines are shown as amino acid sequences of SEQ ID No.1 and SEQ ID No.2 in a sequence table. The vaccines are applied without commercial adjuvants, and can achieve an immune protection effect of over 80 percent.

The invention relates to a multiple-potency live vaccine for fish and an application thereof. The vaccine comprises a recombinant expression vector, which is characterized by comprising an Edwardsiella tarda iron inductive promoter dps with encode operability connected, an Edwardsiella tarda Tat signal peptide coding sequence and an aeromonas hydrophila 3-phosphoglyceraldehyde dehydrogenase coding sequence.

The invention relates to a multiple PCR primer used for simultaneously detecting five pathogenic bacteria and three virulence genes in marine, and a designing method thereof. The method includes: designing a multiple PCR primer composition capable of simultaneously detecting enterococcus faecalis, edwardsiella tarda, carnobacterium, bacillus thuringiensis, vibrio alginolyticus, an enterobacter cloacae gyrB gene, a vibrio parahaemolyticus tlh gene, and an enterococcus faecalis cylA gene by utilization of a primer designing software, screening primers dominant in competitive states, subjecting the primers dominant in the competitive states to amplification and verification by utilization of a PCR method, and finally removing primers weak in the competitive states in the amplification primers so as to obtain a multiple PCR primer composition. A detection method of the multiple PCR is also disclosed. Compared with the prior art, the multiple PCR primer, the designing method and the detection method are advantageous in that: the multiple PCR primer composition simultaneously detecting the five pathogenic bacteria and the three virulence genes in marine has advantages of simple and convenient operation, rapidness, strong specificity, high sensitivity, and the like.

The invention discloses a microbial preparation, and specifically discloses a microbial preparation prepared from pig-derived bacillus licheniformis YHSH-02, and an application of the microbial preparation to aquaculture. The strain disclosed by the invention is preserved in the China General Microbiological Culture Collection Center of China Committee for Culture Collection of Microorganisms at No. 3, No. 1 yard, Beichen West Road, Chaoyang district, Beijing, the preservation number is CGMCC NO.15454, and the preservation date is 15th March, 2018. The bacillus licheniformis YHSH-02 disclosedby the invention is separated from intestines of wild boars, can produce rich small peptide, lipopeptide type bacillin, antibacterial protein and the like, can restrain growth of various aquaculture pathogenic bacteria of vibrio parahaemolyticus, edwardsiella tarda, aeromonas hydrophila, pseudoalteromonas nigrifaciens, vibrio vulnificus and the like, and can be used for preventing and treating aquaculture diseases caused by various bacteria of the vibrio parahaemolyticus, the edwardsiella tarda, the aeromonas hydrophila, the pseudoalteromonas nigrifaciens, the vibrio vulnificus and the like. The situation that the microbial preparation can effectively prevent and treat black-foot diseases of prawns is found for the first time, an effective scheme is provided for preventing and treating theblack-foot diseases of the prawns, and the microbial preparation has important significance. The bacillus licheniformis YHSH-02 obtained from the intestines of the wild boars is a bacterial strain which is high in preventing and treating efficiency, wide in preventing and treating range and notable in growth promotion and has biological preventing and treating potential, and has favorable application and development prospects.

The invention belongs to the technical field of biological medicines, and in particular belongs to an iodine disinfection solution for preventing and treating freshwater biological virus erosion. The iodine disinfection solution comprises the following components in parts by weight: 5-10g of povidone iodine, 1.65-3.3g of potassium iodate, 1.0-2.0g of potassium iodide and a proper amount of a pH adjusting agent. The pH value is adjusted to 5.0-5.5, and water is added to reach 100ml. The iodine disinfection solution disclosed by the invention can be used for effectively preventing and treating various viral diseases of seawater and freshwater aquatic animals, and has relatively good treatment effects on various bacterial diseases caused by pathogenic bacteria such as vibrios, aeromonas hydrophila, edwardsiella tarda, chloroflexi and pseudomonas. In addition, the iodine disinfection solution disclosed by the invention is low in production cost and convenient to use, and is suitable for popularization and application in related technical fields.

The invention relates to a half-smooth tongue sole hepcidin antimicrobial peptide with a sequence of SEQ ID NO: 3. Precursor peptide and mature peptide of the half-smooth tongue sole hepcidin antimicrobial peptide are both products that can be obtained through chemical synthesis and genetic recombination expression. Recombination protein obtained through prokaryotic expression of the half-smooth tongue sole hepcidin antimicrobial peptide has an obvious inhibition effect against the growing of staphylococcus aureus, vibrio anguillarum and Edwardsiella tarda. Compared to other antibacterial peptide, the antibacterial peptide provided by the present invention has a more substantial inhibition effect against sea pathogen. Thus, the antibacterial peptide can be used in aqua culture. Therefore,the half-smooth tongue sole hepcidin antimicrobial peptide provided by the present invention can be applied in the preparation of pathogen resisting products, including feed additives, veterinary drugs, antiseptics, and medicine products such as antibiosis medicine.

The invention provides a fliC protein and GAPDH protein microcapsule vaccine, wherein the antigens are fliC protein and GAPDH protein, the amino acid sequence of the fliC protein is shown as SEQ ID NO:1, and the amino acid sequence of the GAPDH protein is shown as SEQ ID NO:2. The prepared microcapsule vaccine is convenient to use and suitable in grain size, has good slow release feature and antigen protectiveness, and can effectively stimulate a gut immunity system of the fish body to generate immune response, so that the fish body has the specific immunity protection force for Edwardsiella tarda, and therefore, the fliC protein and GAPDH protein microcapsule vaccine can be used for preventing and treating the Edwardsiella tarda disease of the fish.

The invention provides a gene chip for detecting various seawater cultured animal pathogenic bacteria and its application. The pathogenic bacteria include: Vibrio anguillarum, Vibrio alginolyticus, Vibrio parahaemolyticus, Vibrio harveyi, Vibrio fischeri, Vibrio splendidus, Vibrio riverina, Vibrio vulnificus, Vibrio cholerae non-O1, Vibrio mimicus, Vibrio salmonicida, Aeromonas hydrophila, Aeromonas sobria, Aeromonas salmonicida, Edward tarda Bacillus, Edwardsiella catfish, Renalobacter salmonidum, Mycobacterium marinum, Pseudomonas, Streptococcus.

The invention provides a traditional Chinese medicine composition used for inhibiting turbot edwardsiella tarda disease. The traditional Chinese medicine composition consists of the following raw medicinal materials which have better treatment effect within the following dosage range in parts by weight: 100-300 parts of gallnuts, 50-150 parts of scutellaria baicalensis, 100-300 parts of folium isatidis, 100-300 parts of dandelions, 50-150 parts of pomegranate barks and 100-300 parts of humifuse euphorbia herb. The traditional Chinese medicine composition provided by the invention is a pure traditional Chinese medicine preparation, has a better inhibition effect on edwardsiella tarda disease of turbots, is non-toxic and free of pollution, does not generate drug resistance, and is low in price and worthy of development and utilization.

The invention provides four gene deletion mutants of wild edwardsiella tarda (E.tarda) and derivative strains thereof. The four gene deletion mutants are respectively an E.tarda<deltaEvpC> strain with an EvpC gene losing function and derivative strains thereof, an E.tarda<deltaEvpCdeltaEsrB> strain with an EsrB gene losing function and derivative strains thereof, an E.tarda<deltaEvpCdeltaEsrBdeltaPstB> strain with a PstB gene losing function and derivative strains thereof, and an E.tarda<deltaEvpCdeltaEsrBdeltaPstC> strain with a PstC gene losing function and derivative strains thereof. 1-3 genes such as EvpC, EsrB, PstB, PstC and the like of the attenuated strains have parts causing loss of function or suffer from complete deletion, point mutation, shifting or insertion. Compared with a wild 1101 strain or other virulent strains, the E.tarda<deltaEvpC> strain, the E.tarda<deltaEvpCdeltaEsrB> strain, the E.tarda<deltaEvpCdeltaEsrBdeltaPstB> strain and the E.tarda<deltaEvpCdeltaEsrBdeltaPstC> strain have the advantage that the virulence does not exceed 1 / 40, 1 / 400, 1 / 4000 and 1 / 4000 of the virulence of the wild E.tarda 1101 strain or other virulent strains. The genetically engineered attenuated strains of E.tarda can be applied as attenuated vaccine strains of E.tarda, genetic engineering vectors or probiotics.