403
Characteristics of the Pathogen
The original description was extremely brief, referring to the growth of colonies at
very low temperatures, i.e. 1–3 °C, rod-shaped micromorphology, motility, and the
ability to degrade gelatin (Harrison and Sadler 1929 ). The revised description of
Flavobacterium excludes motile organisms (Holmes et al. 1984 ); therefore the
validity of Fla. balustinum was doubtful. The organisms were re-classifi ed to
Chryseobacterium, as Chrys. balustinum on the basis of rRNA clustering
(Vandamme et al. 1994 ). Interestingly, the extensive list of characters in Bergey’s
Manual of Systematic Bacteriology (Holmes et al. 1984 ) precluded reference to
motility or, for that matter, gliding movement among representative strains of any
species. Other characteristics of the taxon included:
Chryseobacterium indologenes
Characteristics of the Disease
In January 2012, mortality was recorded in farmed yellow perch ( Perca fl avescens)
in the USA. The disease signs centred on the presence of yellowish skin lesions,
which were below the dorsal fi n and on the caudal peduncle (Pridgeon et al. 2012 ).
Isolation
Skin lesion samples were inoculated onto Shieh agar supplemented with 1 μg of
tobramycin/ml (Decostere et al. 1997 ) with overnight incubation at 19 +/− 1 °C
(Pridgeon et al. 2012 ).
Box 7.2: Chryseobacterium balustinum
The organism comprises yellow-pigmented, mucoid colonies with nonmotile, oxidative rods of 1.0–1.8 × 0.5 μm in size. Catalase, indole, oxidase
and phosphatase, but not ß-galactosidase, arginine dihydrolase, H 2 S or phenylalanine deaminase, are produced. Nitrates are reduced. Aesculin, casein,
DNA, gelatin, tributyrin, Tween 20 and 80, but not starch, tyrosine or urea, are
degraded. Growth occurs at 37 °C, but not at 5 or 42 °C. This is in contrast to
the original work of Harrison and Sadler ( 1929 ), who reported growth at
almost the freezing point of water. Acid is produced from ethanol and glucose, but not from arabinose, cellobiose, lactose, mannitol, raffi nose, salicin,
sucrose or xylose. The G + C ratio of the DNA is 33.1 moles %.
Chryseobacterium indologenes
Characteristics of the Pathogen
The original description was extremely brief, referring to the growth of colonies at
very low temperatures, i.e. 1–3 °C, rod-shaped micromorphology, motility, and the
ability to degrade gelatin (Harrison and Sadler 1929 ). The revised description of
Flavobacterium excludes motile organisms (Holmes et al. 1984 ); therefore the
validity of Fla. balustinum was doubtful. The organisms were re-classifi ed to
Chryseobacterium, as Chrys. balustinum on the basis of rRNA clustering
(Vandamme et al. 1994 ). Interestingly, the extensive list of characters in Bergey’s
Manual of Systematic Bacteriology (Holmes et al. 1984 ) precluded reference to
motility or, for that matter, gliding movement among representative strains of any
species. Other characteristics of the taxon included:
Chryseobacterium indologenes
Characteristics of the Disease
In January 2012, mortality was recorded in farmed yellow perch ( Perca fl avescens)
in the USA. The disease signs centred on the presence of yellowish skin lesions,
which were below the dorsal fi n and on the caudal peduncle (Pridgeon et al. 2012 ).
Isolation
Skin lesion samples were inoculated onto Shieh agar supplemented with 1 μg of
tobramycin/ml (Decostere et al. 1997 ) with overnight incubation at 19 +/− 1 °C
(Pridgeon et al. 2012 ).
Box 7.2: Chryseobacterium balustinum
The organism comprises yellow-pigmented, mucoid colonies with nonmotile, oxidative rods of 1.0–1.8 × 0.5 μm in size. Catalase, indole, oxidase
and phosphatase, but not ß-galactosidase, arginine dihydrolase, H 2 S or phenylalanine deaminase, are produced. Nitrates are reduced. Aesculin, casein,
DNA, gelatin, tributyrin, Tween 20 and 80, but not starch, tyrosine or urea, are
degraded. Growth occurs at 37 °C, but not at 5 or 42 °C. This is in contrast to
the original work of Harrison and Sadler ( 1929 ), who reported growth at
almost the freezing point of water. Acid is produced from ethanol and glucose, but not from arabinose, cellobiose, lactose, mannitol, raffi nose, salicin,
sucrose or xylose. The G + C ratio of the DNA is 33.1 moles %.
Chryseobacterium indologenes