407
Flavobacterium sp.
Characteristics of the Diseases
Many of these organisms cause gill disease, which may be characterised histologically as hyperplasia (swelling) of the gill epithelia. Frequently, the condition in
juvenile fi sh involves fusion at the distal tips of adjoining gill lamellae. The involvement of hyperplasia-inducing agents has also been implicated in some cases by
Flavobacterium spp. (Kudo and Kimura 1983a , b ).
Isolation
TSA supplemented with 0.5–3.0 % (w/v) sodium chloride was used for the isolation
of Flavobacterium sp. (Acuigrup 1980 ).
Characteristics of the Pathogen
The organisms, discussed by Acuigrup ( 1980 ), were characterised, as follows:
Most of the data originate from use of an unstated API product, possibly the API
20E rapid identifi cation system. The presence of motility contrasts with the revised
defi nition of Flavobacterium (Holmes et al. 1984 ). Therefore, it appears that the organisms are not bona fi de Flavobacterium, but probably represent a closely allied taxon.
Diagnosis
The API 20E rapid identifi cation system has been used for diagnosing Flavobacterium
sp. (Acuigrup 1980 ).
Box 7.6: Flavobacterium sp.
Isolates produce yellow-orange colonies after 24 h (the temperature of incubation was not stated). Cultures comprise motile, pleomorphic, Gram-negative
rods, which produce arginine dihydrolase and oxidase but not ß-galactosidase,
H 2 S, indole or lysine or ornithine decarboxylase, and are neither oxidative nor
fermentative. The Voges Proskauer reaction is positive. Gelatin is degraded.
Acid is produced from amygdalin, arabinose, inositol, mannitol, melibiose
and rhamnose, but not from glucose or lactose. Sodium citrate is not utilised
(Acuigrup 1980 ).
Flavobacterium sp.
Flavobacterium sp.
Characteristics of the Diseases
Many of these organisms cause gill disease, which may be characterised histologically as hyperplasia (swelling) of the gill epithelia. Frequently, the condition in
juvenile fi sh involves fusion at the distal tips of adjoining gill lamellae. The involvement of hyperplasia-inducing agents has also been implicated in some cases by
Flavobacterium spp. (Kudo and Kimura 1983a , b ).
Isolation
TSA supplemented with 0.5–3.0 % (w/v) sodium chloride was used for the isolation
of Flavobacterium sp. (Acuigrup 1980 ).
Characteristics of the Pathogen
The organisms, discussed by Acuigrup ( 1980 ), were characterised, as follows:
Most of the data originate from use of an unstated API product, possibly the API
20E rapid identifi cation system. The presence of motility contrasts with the revised
defi nition of Flavobacterium (Holmes et al. 1984 ). Therefore, it appears that the organisms are not bona fi de Flavobacterium, but probably represent a closely allied taxon.
Diagnosis
The API 20E rapid identifi cation system has been used for diagnosing Flavobacterium
sp. (Acuigrup 1980 ).
Box 7.6: Flavobacterium sp.
Isolates produce yellow-orange colonies after 24 h (the temperature of incubation was not stated). Cultures comprise motile, pleomorphic, Gram-negative
rods, which produce arginine dihydrolase and oxidase but not ß-galactosidase,
H 2 S, indole or lysine or ornithine decarboxylase, and are neither oxidative nor
fermentative. The Voges Proskauer reaction is positive. Gelatin is degraded.
Acid is produced from amygdalin, arabinose, inositol, mannitol, melibiose
and rhamnose, but not from glucose or lactose. Sodium citrate is not utilised
(Acuigrup 1980 ).
Flavobacterium sp.