64
An identifi cation to Str. milleri (probability of a correct identifi cation = 98 %)
resulted from use of the Bacterial Identifi er Program (Bryant and Smith 1991 ). By
means of the API 20 STREP system, an identifi cation of Lactococcus lactis resulted
(probability of a correct identifi cation = 96.7 %). Yet from the published description,
there was a closer fi t with Str. milleri. The only discrepancies concerned utilisation
of citrate, and acid production from inositol, xylitol and xylose. The isolates from
koi carp were positive for these tests.
Pathogenicity
An isolate of Str. milleri (G3K) injected at 5 × 10
6 cells/fi sh caused 20 % mortalities
in Atlantic salmon. Interestingly, all the fi sh darkened, albeit with negligible signs
of internal or external abnormalities. With rainbow trout, there was evidence of
kidney liquefaction (Austin and Robertson 1993 ).
Disease Control
Use of Inhibitory Compounds The two isolates were sensitive to tetracycline,
which might be of value for chemotherapy (Austin and Robertson 1993 ).
Streptococcus parauberis
Characteristics of the Disease
This form of streptococcosis was originally recognised in farmed turbot (weight:
0.8–2 kg) from 5 sites in northern Spain during 1993 and 1994 (Doménech et al.
1996 ), and in northern Portugal in 2004 (Ramos et al. 2012 ). Overall in Spain, the
farms, which used the same fi sh food, reported losses of 0.1–5 %. Disease signs,
which were more severe during summer, included weight loss, haemorrhaging on
the anal and pectoral fi ns, petechial haemorrhages on the abdomen, bilateral exophthalmia, haemorrhaging and pus in the eyes, pale liver, congested kidney and spleen,
ascites, and mucohaemorrhagic enteritis (Doménech et al. 1996 ). The organism has
developed into a major cause of streptococcosis in olive fl ounder (Paralichthys olivaceus) in Asia resulting in heavy mortalities and severe economic loss (Nho et al.
2011 ). Also, there is evidence for its occurrence in wild striped bass in Chesapeake
Bay, USA (Haines et al. 2013 ).
2 Gram-Positive Bacteria (Anaerobes and ‘Lactic Acid’ Bacteria)
An identifi cation to Str. milleri (probability of a correct identifi cation = 98 %)
resulted from use of the Bacterial Identifi er Program (Bryant and Smith 1991 ). By
means of the API 20 STREP system, an identifi cation of Lactococcus lactis resulted
(probability of a correct identifi cation = 96.7 %). Yet from the published description,
there was a closer fi t with Str. milleri. The only discrepancies concerned utilisation
of citrate, and acid production from inositol, xylitol and xylose. The isolates from
koi carp were positive for these tests.
Pathogenicity
An isolate of Str. milleri (G3K) injected at 5 × 10
6 cells/fi sh caused 20 % mortalities
in Atlantic salmon. Interestingly, all the fi sh darkened, albeit with negligible signs
of internal or external abnormalities. With rainbow trout, there was evidence of
kidney liquefaction (Austin and Robertson 1993 ).
Disease Control
Use of Inhibitory Compounds The two isolates were sensitive to tetracycline,
which might be of value for chemotherapy (Austin and Robertson 1993 ).
Streptococcus parauberis
Characteristics of the Disease
This form of streptococcosis was originally recognised in farmed turbot (weight:
0.8–2 kg) from 5 sites in northern Spain during 1993 and 1994 (Doménech et al.
1996 ), and in northern Portugal in 2004 (Ramos et al. 2012 ). Overall in Spain, the
farms, which used the same fi sh food, reported losses of 0.1–5 %. Disease signs,
which were more severe during summer, included weight loss, haemorrhaging on
the anal and pectoral fi ns, petechial haemorrhages on the abdomen, bilateral exophthalmia, haemorrhaging and pus in the eyes, pale liver, congested kidney and spleen,
ascites, and mucohaemorrhagic enteritis (Doménech et al. 1996 ). The organism has
developed into a major cause of streptococcosis in olive fl ounder (Paralichthys olivaceus) in Asia resulting in heavy mortalities and severe economic loss (Nho et al.
2011 ). Also, there is evidence for its occurrence in wild striped bass in Chesapeake
Bay, USA (Haines et al. 2013 ).
2 Gram-Positive Bacteria (Anaerobes and ‘Lactic Acid’ Bacteria)