104
number of vaccine formulations without adjuvants, including a formalised (0.3 % v/v
formaldehyde) suspension of cells grown in KDM2, a lysed cell suspension (this
was lysed at pH 9.5 by the addition of 10 N sodium hydroxide for 1 h, after which
the pH was re-adjusted to 7.2 with 10 N hydrochloric acid), and 50 % concentrates
of the vaccine. Juvenile rainbow trout were vaccinated by i.p. injection, hyperosmotic infi ltration, and by 2 min immersion. Vaccinated fi sh were maintained for
6 weeks at 11 °C and then challenged by i.p. injection with living cells of the homologous organism. Best success occurred with the lysed preparation, administered by
i.p. injection, although failure greeted attempts to vaccinate fi sh by immersion or
hyperosmotic infi ltration. When ≥80 % of the unvaccinated controls were infected,
≤10 % of the vaccinated fi sh were affected. This seems encouraging until it is
realised that the workers measured the presence of infection by the presence of
macroscopic lesions and the occurrence of Gram-positive bacteria in the anterior
part of the kidney. The occurrence of carriers could not be assessed, because the
Gram staining method is not the most sensitive technique for ascertaining the presence of renibacteria. Attenuated cells of Ren. salmoninarum or Arthrobacter davidanieli (Salonius et al. 2005 ) (a commercially available live vaccine named
Renogen) gave limited protection but addition of purifi ed Ren. salmoninarum
genomic DNA or synthetic oligodeoxynucleotides did not improve protection of
chinook salmon following i.p. challenge with a virulent culture (Rhodes et al.
2004b ). More recently, a comparison was made between inactivated whole cells of
two cultures including the type strain without or without prior heating at 37 °C for
48 h that destroys the p57 antigen, a recombinant product based on the p57 antigen
in FIA, Renogen and PBS with or without FIA. Following i.p. injection vaccination,
the chinook salmon were cohabited with mortalities recorded up to 285 days with
the result that protective immunity was not demonstrated in any group (Alcorn et al.
2005 ).
Although renibacterium is normally regarded as being nutritionally fastidious,
two “strains” were isolated from colonies on KDM2 that could grow on regular
laboratory media, i.e. TSA and BHIA., and were non-pathogenic when injected i.p.
into Atlantic salmon at a dose of 5 × 10
6 (Daly et al. 2001 ). When evaluated as live
vaccines, the culture which grew on TSA (= Rs TSA1) led to an RPS of 50 and 74 %
at 74 and 60 days after challenge (Daly et al. 2001 ).
Dietary Supplements Paterson et al. ( 1981 ) discussed the importance of nutrition
in the manifestation of BKD in Atlantic salmon. These workers noted that infected
fi sh had lower serum levels of vitamin A, zinc and iron than uninfected animals.
Subsequent experimentation showed that the level of BKD could be reduced by
feeding with high levels of trace elements, notably cobalt, copper, iodine, iron,
fl uorine and manganese, and reducing the quantity of calcium. In further experiments, Lall et al. ( 1985 ) concluded that high levels of iodine and fl uorine, each
dosed at 45 mg/kg of food, reduced the occurrence of natural infections of BKD to
3 % and 5 %, respectively, as compared to 95 % and 38 % infection in Atlantic
salmon fed with commercial diets. Earlier, Woodall and Laroche ( 1964 ) demonstrated a reduction in BKD infections by feeding chinook salmon with high levels
3 Aerobic Gram-Positive Rods and Cocci
number of vaccine formulations without adjuvants, including a formalised (0.3 % v/v
formaldehyde) suspension of cells grown in KDM2, a lysed cell suspension (this
was lysed at pH 9.5 by the addition of 10 N sodium hydroxide for 1 h, after which
the pH was re-adjusted to 7.2 with 10 N hydrochloric acid), and 50 % concentrates
of the vaccine. Juvenile rainbow trout were vaccinated by i.p. injection, hyperosmotic infi ltration, and by 2 min immersion. Vaccinated fi sh were maintained for
6 weeks at 11 °C and then challenged by i.p. injection with living cells of the homologous organism. Best success occurred with the lysed preparation, administered by
i.p. injection, although failure greeted attempts to vaccinate fi sh by immersion or
hyperosmotic infi ltration. When ≥80 % of the unvaccinated controls were infected,
≤10 % of the vaccinated fi sh were affected. This seems encouraging until it is
realised that the workers measured the presence of infection by the presence of
macroscopic lesions and the occurrence of Gram-positive bacteria in the anterior
part of the kidney. The occurrence of carriers could not be assessed, because the
Gram staining method is not the most sensitive technique for ascertaining the presence of renibacteria. Attenuated cells of Ren. salmoninarum or Arthrobacter davidanieli (Salonius et al. 2005 ) (a commercially available live vaccine named
Renogen) gave limited protection but addition of purifi ed Ren. salmoninarum
genomic DNA or synthetic oligodeoxynucleotides did not improve protection of
chinook salmon following i.p. challenge with a virulent culture (Rhodes et al.
2004b ). More recently, a comparison was made between inactivated whole cells of
two cultures including the type strain without or without prior heating at 37 °C for
48 h that destroys the p57 antigen, a recombinant product based on the p57 antigen
in FIA, Renogen and PBS with or without FIA. Following i.p. injection vaccination,
the chinook salmon were cohabited with mortalities recorded up to 285 days with
the result that protective immunity was not demonstrated in any group (Alcorn et al.
2005 ).
Although renibacterium is normally regarded as being nutritionally fastidious,
two “strains” were isolated from colonies on KDM2 that could grow on regular
laboratory media, i.e. TSA and BHIA., and were non-pathogenic when injected i.p.
into Atlantic salmon at a dose of 5 × 10
6 (Daly et al. 2001 ). When evaluated as live
vaccines, the culture which grew on TSA (= Rs TSA1) led to an RPS of 50 and 74 %
at 74 and 60 days after challenge (Daly et al. 2001 ).
Dietary Supplements Paterson et al. ( 1981 ) discussed the importance of nutrition
in the manifestation of BKD in Atlantic salmon. These workers noted that infected
fi sh had lower serum levels of vitamin A, zinc and iron than uninfected animals.
Subsequent experimentation showed that the level of BKD could be reduced by
feeding with high levels of trace elements, notably cobalt, copper, iodine, iron,
fl uorine and manganese, and reducing the quantity of calcium. In further experiments, Lall et al. ( 1985 ) concluded that high levels of iodine and fl uorine, each
dosed at 45 mg/kg of food, reduced the occurrence of natural infections of BKD to
3 % and 5 %, respectively, as compared to 95 % and 38 % infection in Atlantic
salmon fed with commercial diets. Earlier, Woodall and Laroche ( 1964 ) demonstrated a reduction in BKD infections by feeding chinook salmon with high levels
3 Aerobic Gram-Positive Rods and Cocci