405
Pathogenicity
It was stated that infectivity experiments confi rmed pathogenicity of Chry. piscicola
for Atlantic salmon (Ilardi et al. 2010 ).
Chryseobacterium scophthalmum (= Flavobacterium
scophthalmum)
Characteristics of the Disease
This organism caused lethargy, gill hyperplasia, haemorrhaging in the gills, distended abdomen, surface haemorrhaging, and extensive internal haemorrhaging
(Mudarris and Austin 1989 , 1992 ).
Isolation
The pathogen may be recovered from infected tissues on medium K (Appendix in
Chap. 12 ; Mudarris and Austin 1989 ).
Box 7.4: Chryseobacterium piscicola
Colonies are yellow [produces fl exirubin pigment], smooth, shine and circular, and comprise Gram-negative, non-motile, non-gliding, non-fermentative
α– haemolytic rods of 1.6–3.5 μm in length and 0.8–1.2 mm in diameter that
produce catalase and oxidase. Growth occurs at 4–28 °C but not at 37 °C and
in 0–3 % (w/v) sodium chloride. Nitrates are not reduced. Aesculin, DNA
(weakly) and gelatin are degraded, but not agar, casein, starch, Tween 80,
tyrosine or urea. H 2 S and indole are not produced. Neither arginine dihydrolase, or lysine or ornithine decarboxylase is produced. The methyl red test and
Voges Proskauer reaction are negative. Acid and alkaline phosphatase, esterase, esterase lipase, lipase, cysteine leucine and valine arylamidase, α–chymotrypsin, naphthol-AS-BI-phosphohydrolase, ß-glucuronidase, α– and
ß-glucosidase and N -acetyl-ß-glucosaminidase were produced in the API
ZYM system, but not α–fucosidase, α– or ß-galactosidase, α–mannosidase or
trypsin. The G + C ratio of the DNA of the two cultures examined is 32.5- and
32.3 moles %. Examination of the 16S rRNA gene sequences confi rmed
membership of the genus Chryseobacterium (Ilardi et al. 2009 , 2010 ).
Chryseobacterium scophthalmum (= Flavobacterium scophthalmum)
Pathogenicity
It was stated that infectivity experiments confi rmed pathogenicity of Chry. piscicola
for Atlantic salmon (Ilardi et al. 2010 ).
Chryseobacterium scophthalmum (= Flavobacterium
scophthalmum)
Characteristics of the Disease
This organism caused lethargy, gill hyperplasia, haemorrhaging in the gills, distended abdomen, surface haemorrhaging, and extensive internal haemorrhaging
(Mudarris and Austin 1989 , 1992 ).
Isolation
The pathogen may be recovered from infected tissues on medium K (Appendix in
Chap. 12 ; Mudarris and Austin 1989 ).
Box 7.4: Chryseobacterium piscicola
Colonies are yellow [produces fl exirubin pigment], smooth, shine and circular, and comprise Gram-negative, non-motile, non-gliding, non-fermentative
α– haemolytic rods of 1.6–3.5 μm in length and 0.8–1.2 mm in diameter that
produce catalase and oxidase. Growth occurs at 4–28 °C but not at 37 °C and
in 0–3 % (w/v) sodium chloride. Nitrates are not reduced. Aesculin, DNA
(weakly) and gelatin are degraded, but not agar, casein, starch, Tween 80,
tyrosine or urea. H 2 S and indole are not produced. Neither arginine dihydrolase, or lysine or ornithine decarboxylase is produced. The methyl red test and
Voges Proskauer reaction are negative. Acid and alkaline phosphatase, esterase, esterase lipase, lipase, cysteine leucine and valine arylamidase, α–chymotrypsin, naphthol-AS-BI-phosphohydrolase, ß-glucuronidase, α– and
ß-glucosidase and N -acetyl-ß-glucosaminidase were produced in the API
ZYM system, but not α–fucosidase, α– or ß-galactosidase, α–mannosidase or
trypsin. The G + C ratio of the DNA of the two cultures examined is 32.5- and
32.3 moles %. Examination of the 16S rRNA gene sequences confi rmed
membership of the genus Chryseobacterium (Ilardi et al. 2009 , 2010 ).
Chryseobacterium scophthalmum (= Flavobacterium scophthalmum)