Aeromonas salmonicida is a species of Gram-negative bacteria, from the genus Aeromonas, which causes the disease furunculosis in marine and freshwater fish. The symptoms the fish show are external and internal hemorrhaging, swelling of the vents and kidneys, boils, ulcers, liquefaction, and gastroenteritis. Furunculosis is commonly known as tail rot in fish and is common in gold and koi fish. Infected fish with open sores are able to spread the disease to other fish. It is also responsible for bald sea urchin disease.
Most strands of the bacterium are non-motile. It is bacillus in shape. The short rods have rounded ends which allow it to be easily confused as a coccus. Aeromonas salmonicida is a facultative anaerobe which means that it is capable of making ATP by aerobic respiration if oxygen is present but is also capable of switching to fermentation when oxygen is not present. It does not ferment sucrose or lactose, using glucose in this pathway instead; glucose fermentation creates gas (Wiki: Aeromonas salmonicida).
4. Host Ranges and Animal Models
All species of salmon, trout, charr and grayling are susceptible to infection with Aeromonas salmonicida (USGS Fish Disease Leaflets).
Protein Name :
3-phosphoshikimate 1-carboxyvinyltransferase
Protein pI :
6.3
Protein Weight :
43170.95
Protein Length :
427
Protein Note :
catalyzes the formation of 5-O-(1-carboxyvinyl)-3-phosphoshikimate from phosphoenolpyruvate and 3-phosphoshikimate in tryptophan biosynthesis
Molecule Role Annotation :
The aroA gene was inactivated by inserting a fragment expressing kanamycin resistance within the coding sequence and challenged in fish. The LD50 for unvaccinated fish was 7.1 x 101. In contrast, the LD50 was 1.8 x 104 in fish vaccinated once and 3 x 105 in fish vaccinated twice (Vaughan et al., 1993).
Molecule Role Annotation :
The aroA gene of A. salmonicida was cloned in Escherichia coli, and the nucleotide sequence was determined. Vaccination of brown trout with 10(7) CFU of A. salmonicida 644Rb aroA by intraperitoneal injection resulted in a 253-fold increase in the 50% lethal dose (LD50) compared with unvaccinated controls challenged with a virulent clinical isolate 9 weeks later (Vaughan et al., 1993).
Molecule Role Annotation :
Passive immunisation of Atlantic salmon with rainbow trout or rabbit anti-AsaP1 antisera conferred significant protection against challenge with a virulent A. salmonicida (Gudmundsdottir et al., 1997)
III. Vaccine Information
1. A. salmonicida live-attenuated vaccine encoding AroA
Description:
The aroA gene of A. salmonicida was cloned in Escherichia coli, and the nucleotide sequence was determined. The aroA gene was inactivated by inserting a fragment expressing kanamycin resistance within the coding sequence. The aroA::Kar mutation was introduced into the chromosome of virulent A. salmonicida 644Rb and 640V2 by allele replacement by using a suicide plasmid delivery system. The mutation resulted in attenuation when bacteria were injected intramuscularly into Atlantic salmon (Vaughan et al., 1993).
Vaccination Protocol:
Brown trout were vaccinated with 10^7 CFU of A. salmonicida 644Rb aroa by intraperitoneal injection (Vaughan et al., 1993).
Challenge Protocol:
Groups of four or five fish were challenged by intramuscular injection of dilutions of cultures of a virulent strain of A. salmonicida (Vaughan et al., 1993).
Efficacy:
Vaccination of brown trout with 10^7 CFU of A. salmonicida 644Rb aroA by intraperitoneal injection resulted in a 253-fold increase in the 50% lethal dose (LD50) compared with unvaccinated controls challenged with a virulent clinical isolate 9 weeks later. A second vaccination after 6 weeks increased the LD50 by a further 16-fold (Vaughan et al., 1993).
1. Bergh et al., 2013: Bergh PV, Burr SE, Benedicenti O, von Siebenthal B, Frey J, Wahli T. Antigens of the type-three secretion system of Aeromonas salmonicida subsp. salmonicida prevent protective immunity in rainbow trout. Vaccine. 2013; 31(45); 5256-5261. [PubMed: 24012573].
2. Gudmundsdottir et al., 1997: BJARNHEIDUR K. GUDMUNDSDÓTTIR, BERGLJÓT MAGNADÓTTIR. Protection of Atlantic salmon (Salmo salarL.) against an experimental infection ofAeromonas salmonicidassp.achromogenes. Fish & shellfish immunology. 1997; 7(1); 55-69.
3. Lund et al., 2003: Lund V, Espelid S, Mikkelsen H. Vaccine efficacy in spotted wolffish Anarhichas minor: relationship to molecular variation in A-layer protein of atypical Aeromonas salmonicida. Diseases of aquatic organisms. 2003; 56(1); 31-42. [PubMed: 14524499].
4. Sundvold et al., 2010: Sundvold H, Ruyter B, Ostbye TK, Moen T. Identification of a novel allele of peroxisome proliferator-activated receptor gamma (PPARG) and its association with resistance to Aeromonas salmonicida in Atlantic salmon (Salmo salar). Fish & shellfish immunology. 2010; 28(2); 394-400. [PubMed: 20004720].
6. Vaughan et al., 1993: Vaughan LM, Smith PR, Foster TJ. An aromatic-dependent mutant of the fish pathogen Aeromonas salmonicida is attenuated in fish and is effective as a live vaccine against the salmonid disease furunculosis. Infection and immunity. 1993; 61(5); 2172-2181. [PubMed: 8478107].
