Attenuated strains of Aeromonas salmonicida useful as fish vaccines

• US 5,498,414 A
• Filed: 10/05/1992
• Issued: 03/12/1996
• Est. Priority Date: 10/05/1992
• Status: Expired due to Term

• Current Assignee: 0337609 B.C. Ltd.
• Original Assignee: University of Victoria
• Inventors: Thornton, Julian C., Kay, William W.
• Primary Examiner(s): Sidberry, Hazel F.
• Assistant Examiner(s): KRSEK STAPLES, JULIE
• Application Number:
  US07/957,531
• Time in Patent Office: 1,254 Days
• Field of Search: 424/92, 424/234.1, 424/827, 435/243, 435/252.1, 435/245
• US Class Current: 424/234.1
• CPC Class Codes: A61K 2039/552 Veterinary vaccine
• CPC Class Codes: A61K 39/0208 Specific bacteria not otherwise provided for
• CPC Class Codes: C12N 1/205 Bacterial isolates
• CPC Class Codes: C12R 2001/01 Bacteria or Actinomycetales ; using bacteria or Actinomycetales
• CPC Class Codes: Y10S 424/827 Bacterial vaccine for fish

Abstract

Novel attenuated strains of Aeromonas salmonicida are disclosed that are effective as live effective vaccines against furunculosis in fish. These vaccines may be administered by the immersion of fish in a solution of the vaccine. Methods of producing these strains and other strains having the identifying characteristics of these strains are also disclosed.

Claims

1. A live vaccine for the immunization of fish wherein the vaccine comprises live microorganisms selected from the group consisting of:

Aeromonas salmonicida strain 10SR or mutants thereof that are capable of inducing protective immunity in a susceptible fish against infection by virulent Aeromonas salmonicida;

Aeromonas salmonicida strain 10SR-3 or mutants thereof that are capable of inducing protective immunity in a susceptible fish against infection by virulent Aeromonas salmonicida; and

Aeromonas salmonicida strain A450-3 or mutants thereof that are capable of inducing protective immunity against infection by virulent Aeromonas salmonicida in susceptible fish.

2. The live vaccine of claim 1, wherein the vaccine is capable of inducing protective immunity against infection by virulent Aeromonas salmonicida in a susceptible fish when administered by immersion of the fish for a sufficient number of times in a solution containing a sufficient amount of the live vaccine for a sufficient period of time to reduce the susceptibility of the fish to infection by virulent Aeromonas salmonicida.

3. A method of reducing the susceptibility of fish to infection by virulent strains of Aeromonas salmonicida wherein the method comprises exposing fish to a sufficient amount of the live vaccine of claim 1 so as to reduce the susceptibility of the fish to infection by virulent Aeromonas salmonicida.

4. The method of claim 3 wherein the exposing step comprises immersing the fish for a sufficient number of times in a solution containing a sufficient amount of the live vaccine for a sufficient period of time to reduce the susceptibility of the fish to infection by virulent Aeromonas salmonicida.

5. The method of claim 4 wherein the exposing step provides a Protective Index greater than 20 in the fish immersed in the solution.

6. The method of claim 4 wherein the exposing step provides a Protective Index of greater than 100 in susceptible fish immersed in the solution.

7. The method of claim 4 wherein the exposing step comprises immersing the fish twice in the solution containing the sufficient amount of the live vaccine for the sufficient period of time to reduce the susceptibility of the fish to infection by virulent Aeromonas salmonicida.

8. The method of claim 7 wherein the exposing step provides a Protective Index of greater than 100 in susceptible fish immersed in the solution.

9. The method of claim 3 wherein the exposing step comprises intraperitoneal injection of the vaccine into the fish.

10. A live vaccine for the immunization of fish wherein the live vaccine comprises an attenuated strain of Aeromonas salmonicida wherein said strain does not possess an A-layer.

11. The live vaccine of claim 10 wherein the vaccine comprises the live vaccine in a container with a preservative suitable for maintaining the viability of the live vaccine.

12. The live vaccine of claim 10 wherein the vaccine is capable of reducing the susceptibility of a susceptible fish to infection by virulent Aeromonas salmonicida when the fish is exposed to the vaccine by immersion of the fish for a sufficient number of times in a solution containing a sufficient amount of the live vaccine for a sufficient period of time to reduce the susceptibility of the fish to infection by virulent Aeromonas salmonicida.

13. The live vaccine of claim 12 wherein the vaccine produces a protective index of greater than 100 when susceptible fish are twice immersed in a solution of the vaccine for a period of 30 minutes, said immersions being 14 days apart and said solution containing 5×

10⁸ cells/ml of the microorganisms comprising the vaccine.

14. A method of reducing the susceptibility of fish to infection by virulent strains of Aeromonas salmonicida wherein the method comprises exposing fish to a sufficient amount of the vaccine of claim 10 so as to reduce the susceptibility of the fish to infection by virulent Aeromonas salmonicida.

32. The method of claim 14 wherein the exposing step comprises immersing the fish for a sufficient number of times in a solution containing a sufficient amount of the live vaccine for a sufficient period of time to reduce the susceptibility of the fish to infection by virulent Aeromonas salmonicida.

33. The method of claim 32 wherein the exposing step comprises immersing the fish twice in the solution containing the sufficient amount of the live vaccine for the sufficient period of time to reduce the susceptibility of the fish to infection by virulent Aeromonas salmonicida.

34. The method of claim 14 wherein the exposing step comprises intraperitoneal injection of the vaccine into the fish.

15. A live vaccine for the immunization of fish wherein the vaccine comprises Aeromonas salmonicida strain 10SR or mutants thereof that are capable of inducing protective immunity in a susceptible fish against infection by virulent Aeromonas salmonicida.

16. A method of reducing the susceptibility of a fish to infection by virulent strains of Aeromonas salmonicida wherein the method comprises exposing the fish to a sufficient amount of the live vaccine of claim 15 to reduce the susceptibility of the fish to infection by virulent Aeromonas salmonicida.

17. A live vaccine for the immunization of fish wherein the vaccine comprising Aeromonas salmonicida strain 10SR-3 or mutants thereof that are capable of inducing protective immunity against infection By virulent Aeromonas salmonicida in susceptible fish.

18. A method of reducing the susceptibility of a fish to infection by virulent strains of Aeromonas salmonicida wherein the method comprises exposing the fish to a sufficient amount of the live vaccine of claim 17 to reduce the susceptibility of the fish to infection by virulent Aeromonas salmonicida.

19. A live vaccine for the immunization of fish wherein the vaccine comprises Aeromonas salmonicida strain A450-3 or mutants thereof that are capable of inducing protective immunity against infection by virulent Aeromonas salmonicida in susceptible fish.

20. A method of reducing the susceptibility of a fish to infection by virulent strains of Aeromonas salmonicida wherein the method comprises exposing the fish to a sufficient amount of the live vaccine of claim 19 to reduce the susceptibility of the fish to infection by virulent Aeromonas salmonicida.

21. An attenuated Aeromonas salmonicida microorganism selected from the group consisting of:

Aeromonas salmonicida strain 10S;

Aeromonas salmonicida strain 10SR; and

Aeromonas salmonicida strain 10SR-3.

22. The microorganism of claim 21 wherein said microorganism is present in a biologically pure culture.

23. The microorganism of claim 21 wherein the microorganism is Aeromonas salmonicida strain 10S.

24. The microorganism of claim 21 wherein the microorganism is Aeromonas salmonicida strain 10SR.

25. The microorganism of claim 21 wherein the microorganism is Aeromonas salmonicida strain 10SR-3.

26. A live vaccine for the immunization of fish wherein the vaccine comprises microorganisms selected from the group consisting of Aeromonas salmonicida 10SR, Aeromonas salmonicida 10SR-3 and Aeromonas salmonicida A450-3.

27. The vaccine of claim 26 wherein the vaccine comprises Aeromonas salmonicida 10SR.

28. The vaccine of claim 26 wherein the vaccine comprises Aeromonas salmonicida 10SR-3.

29. The vaccine of claim 26 wherein the vaccine comprises Aeromonas salmonicida A450-3.

30. A method of reducing the susceptibility of a fish to infection by a virulent strain of Aeromonas salmonicida wherein the method comprises immersing the fish in a solution of the vaccine according to claim 26.

31. The method of claim 30 wherein the method comprises immersing the fish for a sufficient number of times in a solution containing a sufficient amount of the vaccine for a sufficient period of time to reduce the susceptibility of the fish to infection by the virulent strain of Aeromonas salmonicida.