39
Although there are insuffi cient data for a meaningful comparison with other taxa,
it is interesting to note that streptococci are normally associated with the production
of white colonies.
Vagococcus salmoninarum
Characteristics of the Disease
In France, the organism was attributed to signifi cant losses, i.e. up to 50 % in a year,
in rainbow trout farmed at low water temperature (Michel et al. 1997 ). Disease signs
included listless behaviour, impaired swimming, unilateral exophthalmia, external
haemorrhages, petechial haemorrhages on the gills, and enlarged liver and spleen
(Michel et al. 1997 ) and peritonitis (Schmidtke and Carson 1994 ). Subsequently in
rainbow trout farmed in Turkey, the organism was associated with ~55 % mortalities, and disease signs including anorexia, lethargy, darkened pigmentation, exophthalmia, disruption of the eyeball, boils, erosion on the side of the body,
haemorrhaging in the jaw, mouth, abdomen and anus, and prolapse of the anus
Didinen et al. 2011 ). The pathogen was detected in the heart and kidney of diseased
rainbow trout Cagatay and Gumus 2014 )).
Isolation
Schmidtke and Carson ( 1994 ) used Oxoid blood agar base supplemented with 7 %
(v/v) defi brinated sheep blood with incubation at 25 °C for 48 h to recover cultures
from brain, kidney, peritoneum, spleen and testes.
Characteristics of the Pathogen
In 1968, a so-called lactobacillus was recovered from diseased adult rainbow trout
in Oregon, USA and later subjected to detailed taxonomic examination. This isolate, designated OS1-68
T
, has become the type strain of Vagococcus salmoninarum
Box 2.7: Enterococcus faecalis subsp. liquefaciens
Yellow colonies of 1–2 mm in diameter are obtained from kidney and liver on
TSA. Colonies comprise Gram-positive cocci, which do not produce catalase,
H 2 S or indole and are negative for the methyl red test and the Voges Proskauer
reaction. Nitrates are reduced. DNA and gelatin are attacked. Citrate is
utilised.
Enterococcaceae Representatives
Although there are insuffi cient data for a meaningful comparison with other taxa,
it is interesting to note that streptococci are normally associated with the production
of white colonies.
Vagococcus salmoninarum
Characteristics of the Disease
In France, the organism was attributed to signifi cant losses, i.e. up to 50 % in a year,
in rainbow trout farmed at low water temperature (Michel et al. 1997 ). Disease signs
included listless behaviour, impaired swimming, unilateral exophthalmia, external
haemorrhages, petechial haemorrhages on the gills, and enlarged liver and spleen
(Michel et al. 1997 ) and peritonitis (Schmidtke and Carson 1994 ). Subsequently in
rainbow trout farmed in Turkey, the organism was associated with ~55 % mortalities, and disease signs including anorexia, lethargy, darkened pigmentation, exophthalmia, disruption of the eyeball, boils, erosion on the side of the body,
haemorrhaging in the jaw, mouth, abdomen and anus, and prolapse of the anus
Didinen et al. 2011 ). The pathogen was detected in the heart and kidney of diseased
rainbow trout Cagatay and Gumus 2014 )).
Isolation
Schmidtke and Carson ( 1994 ) used Oxoid blood agar base supplemented with 7 %
(v/v) defi brinated sheep blood with incubation at 25 °C for 48 h to recover cultures
from brain, kidney, peritoneum, spleen and testes.
Characteristics of the Pathogen
In 1968, a so-called lactobacillus was recovered from diseased adult rainbow trout
in Oregon, USA and later subjected to detailed taxonomic examination. This isolate, designated OS1-68
T
, has become the type strain of Vagococcus salmoninarum
Box 2.7: Enterococcus faecalis subsp. liquefaciens
Yellow colonies of 1–2 mm in diameter are obtained from kidney and liver on
TSA. Colonies comprise Gram-positive cocci, which do not produce catalase,
H 2 S or indole and are negative for the methyl red test and the Voges Proskauer
reaction. Nitrates are reduced. DNA and gelatin are attacked. Citrate is
utilised.
Enterococcaceae Representatives