483
Pathogenicity
The original description by López et al. ( 2011 ) included confi rmation that one culture, A390
T
, caused mortalities in wedge sole following i.p. (10
6 cells/fi sh) but not
bath challenge (18 h in 10
7 cells/ml). In comparison to the natural infection, experimentally challenged fi sh did not reveal any overt signs of disease.
Pseudomonas chlororaphis
Characteristics of the Disease
In moribund fry, it was observed that symptoms included the presence of distended
abdomen with ascitic fl uid, and haemorrhages on the body surface (Hatai et al.
1975 ).
Isolation
This may be accomplished by inoculating homogenates, prepared from the entire
fi sh, onto the surface of nutrient agar plates, with incubation at 25 °C for 5 days. It
is surprising that this simple method enabled the recovery of pure cultures, because
contaminants may be expected from the intestine and body surface (Hatai et al.
1975 ).
Box 9.3: Pseudomonas baetica
Cultures are whitish and up to 0.5 mm in diameter after incubation for 48 h,
and comprise fl uorescent [with fl uorescein] large irregularly shaped haemolytic Gram-negative strictly aerobic, motile rods that produce acid and alkaline (mostly) phosphatase, α-chemotrypsin, arginine dihydrolase, catalase,
cystine arylamidase, esterase (C4) (mostly), esterase lipase (C8), leucine arylamidase (mostly) and oxidase, but not N-acetyl-ß-glucosaminidase,
α-fucosidase, α– or ß-galactosidase, ß-glucuronidase,, α– or ß-glucosidase,
H 2 S, lipase (C14), α-mannosidase, lysine or ornithine decarboxylase,
naphthol- AS-BI-phosphohydrolase, trypsin or valine arylamindase. Casein
and gelatin are degraded, but not aesculin, starch, Tween 80 or urea. Nitrates
are not reduced to nitrite. The Voges Proskauer reaction is negative. Citrate is
utilised. Growth occurs at 4–30 °C and in 0–6 % (w/v) sodium chloride. Acid
is produced from glucose and mannose, but not from amygdalin, arabinose,
inositol, lactose, mannitol rhamnose, salicin or sorbitol (López et al. 2011 ).
Pseudomonas chlororaphis
Pathogenicity
The original description by López et al. ( 2011 ) included confi rmation that one culture, A390
T
, caused mortalities in wedge sole following i.p. (10
6 cells/fi sh) but not
bath challenge (18 h in 10
7 cells/ml). In comparison to the natural infection, experimentally challenged fi sh did not reveal any overt signs of disease.
Pseudomonas chlororaphis
Characteristics of the Disease
In moribund fry, it was observed that symptoms included the presence of distended
abdomen with ascitic fl uid, and haemorrhages on the body surface (Hatai et al.
1975 ).
Isolation
This may be accomplished by inoculating homogenates, prepared from the entire
fi sh, onto the surface of nutrient agar plates, with incubation at 25 °C for 5 days. It
is surprising that this simple method enabled the recovery of pure cultures, because
contaminants may be expected from the intestine and body surface (Hatai et al.
1975 ).
Box 9.3: Pseudomonas baetica
Cultures are whitish and up to 0.5 mm in diameter after incubation for 48 h,
and comprise fl uorescent [with fl uorescein] large irregularly shaped haemolytic Gram-negative strictly aerobic, motile rods that produce acid and alkaline (mostly) phosphatase, α-chemotrypsin, arginine dihydrolase, catalase,
cystine arylamidase, esterase (C4) (mostly), esterase lipase (C8), leucine arylamidase (mostly) and oxidase, but not N-acetyl-ß-glucosaminidase,
α-fucosidase, α– or ß-galactosidase, ß-glucuronidase,, α– or ß-glucosidase,
H 2 S, lipase (C14), α-mannosidase, lysine or ornithine decarboxylase,
naphthol- AS-BI-phosphohydrolase, trypsin or valine arylamindase. Casein
and gelatin are degraded, but not aesculin, starch, Tween 80 or urea. Nitrates
are not reduced to nitrite. The Voges Proskauer reaction is negative. Citrate is
utilised. Growth occurs at 4–30 °C and in 0–6 % (w/v) sodium chloride. Acid
is produced from glucose and mannose, but not from amygdalin, arabinose,
inositol, lactose, mannitol rhamnose, salicin or sorbitol (López et al. 2011 ).
Pseudomonas chlororaphis