128
following incubation aerobically at 25–37 °C for an undisclosed period (Appendix
in Chap. 12 ; Rucker 1949 ).
Characteristics of the Pathogen
Streptomycoccis in fi sh was described initially by Rucker ( 1949 ), who classifi ed the
aetiological agent in Streptomyces, as Streptomyces salmonicida. This was amended
initially to Verticillomyces salmonicida (Shinobu 1965 ), then to Streptoverticillium
salmonicida (Baldacci et al. 1966 ), Streptoverticillium salmonis (Locci et al. 1969 )
Streptomyces salmonis (Witt and Stackebrandt 1990 ) and fi nally to Noc. salmonicida (Isik et al. 1999 ). In general, a dearth of information exists about this fi sh
pathogen. Essentially, since the work of Rucker ( 1949 ), the disease has received
limited attention. Therefore, it is diffi cult to decide whether or not streptomycoccis
represents a genuine problem.
Box 3.17: Nocardia salmonicida
The organism produces brick red to orange pigmented substrate mycelia with
white (with pink and yellow shades) aerial mycelia. On primary isolation, the
colonies are small and, initially, smooth, but later they develop aerial mycelia
that appear velvety. Characteristically, the aerial mycelia produce whorls (verticils) at frequent intervals, giving an appearance of barbed wire. The Grampositive catalase-positive non-motile mycelia contain LL-diaminopimelic
acid (DAP) and glycine but not meso-DAP, arabinose or galactose in the cell
wall (i.e. Type I). Melanin, but generally not H 2 S, is produced. Aesculin,
DNA, gelatin, starch, testosterone, Tween 20 (some isolates), Tween 20, tyrosine and urea are degraded, but not adenine, casein, cellulose, chitin, elastin,
guanine, hypoxanthine, starch, uric acid, xanthine or xanthan. Nitrates are
reduced. Growth occurs at 12° and 30 °C but not at 35 °C, in 53 % (w/v)
sodium chloride, 0.0001 % (w/v) bismuth citrate, 0.00001 % (w/v) crystal violet, 0.01 % (w/v) phenol and 0.01 % (w/v) potassium tellurite, but not in or
0.01 % (w/v) malachite green or 0.01 % (w/v) sodium azide. Acid is produced
from glucose, glycerol, inositol, ribose and trehalose, and slightly from
sucrose, but not from arabinose, cellulose, erythritol, fructose, galactose,
maltose, mannose, mannitol, raffi nose, rhamnose, trehalose or xylose.
Butyrate, citrate, fumarate, D-fructose, D(+)-glucose, malate, D(+)-mannitol,
L-proline, propionate, D(+)-sorbitol and succinate are utilised, but not amygdalin, D and L-arabinose, arbutin, D(+)-cellobiose, dulcitol, D(+)-galactose,
glycogen, m -inositol, inulin, D(+)-melezitose, D(+)-raffi nose, L-rhamnose,
acetamide, acetate, anthranilic acid, benzoate, 1,4-butanediol, 2,3-butanediol,
hippurate, 4-hydroxybenzoate, lactate, malonate, 2-octanol, pimelic acid or
tartrate (Williams et al. 1985 ; Isik et al. 1999 ). The major cellular fatty acids
are hexadecanoic, octadecanoic, octadecanoic and 10-methyloctadecanoic
acid. The G + C ratio of the DNA is 67 mol% (Isik et al. 1999 ).
3 Aerobic Gram-Positive Rods and Cocci
following incubation aerobically at 25–37 °C for an undisclosed period (Appendix
in Chap. 12 ; Rucker 1949 ).
Characteristics of the Pathogen
Streptomycoccis in fi sh was described initially by Rucker ( 1949 ), who classifi ed the
aetiological agent in Streptomyces, as Streptomyces salmonicida. This was amended
initially to Verticillomyces salmonicida (Shinobu 1965 ), then to Streptoverticillium
salmonicida (Baldacci et al. 1966 ), Streptoverticillium salmonis (Locci et al. 1969 )
Streptomyces salmonis (Witt and Stackebrandt 1990 ) and fi nally to Noc. salmonicida (Isik et al. 1999 ). In general, a dearth of information exists about this fi sh
pathogen. Essentially, since the work of Rucker ( 1949 ), the disease has received
limited attention. Therefore, it is diffi cult to decide whether or not streptomycoccis
represents a genuine problem.
Box 3.17: Nocardia salmonicida
The organism produces brick red to orange pigmented substrate mycelia with
white (with pink and yellow shades) aerial mycelia. On primary isolation, the
colonies are small and, initially, smooth, but later they develop aerial mycelia
that appear velvety. Characteristically, the aerial mycelia produce whorls (verticils) at frequent intervals, giving an appearance of barbed wire. The Grampositive catalase-positive non-motile mycelia contain LL-diaminopimelic
acid (DAP) and glycine but not meso-DAP, arabinose or galactose in the cell
wall (i.e. Type I). Melanin, but generally not H 2 S, is produced. Aesculin,
DNA, gelatin, starch, testosterone, Tween 20 (some isolates), Tween 20, tyrosine and urea are degraded, but not adenine, casein, cellulose, chitin, elastin,
guanine, hypoxanthine, starch, uric acid, xanthine or xanthan. Nitrates are
reduced. Growth occurs at 12° and 30 °C but not at 35 °C, in 53 % (w/v)
sodium chloride, 0.0001 % (w/v) bismuth citrate, 0.00001 % (w/v) crystal violet, 0.01 % (w/v) phenol and 0.01 % (w/v) potassium tellurite, but not in or
0.01 % (w/v) malachite green or 0.01 % (w/v) sodium azide. Acid is produced
from glucose, glycerol, inositol, ribose and trehalose, and slightly from
sucrose, but not from arabinose, cellulose, erythritol, fructose, galactose,
maltose, mannose, mannitol, raffi nose, rhamnose, trehalose or xylose.
Butyrate, citrate, fumarate, D-fructose, D(+)-glucose, malate, D(+)-mannitol,
L-proline, propionate, D(+)-sorbitol and succinate are utilised, but not amygdalin, D and L-arabinose, arbutin, D(+)-cellobiose, dulcitol, D(+)-galactose,
glycogen, m -inositol, inulin, D(+)-melezitose, D(+)-raffi nose, L-rhamnose,
acetamide, acetate, anthranilic acid, benzoate, 1,4-butanediol, 2,3-butanediol,
hippurate, 4-hydroxybenzoate, lactate, malonate, 2-octanol, pimelic acid or
tartrate (Williams et al. 1985 ; Isik et al. 1999 ). The major cellular fatty acids
are hexadecanoic, octadecanoic, octadecanoic and 10-methyloctadecanoic
acid. The G + C ratio of the DNA is 67 mol% (Isik et al. 1999 ).
3 Aerobic Gram-Positive Rods and Cocci