122
Myc. pseudoshottsi (Rhodes et al. 2005 ).
Myc. salmoniphilum was revived as a valid species name (Whipps et al. 2007 ),
and has since been recognised as a cause of disease with mortalities in Norwegian
farmed Atlantic salmon, which displayed greyish-white nodules in the viscera
(Zerihun et al. 2011c ).
Myc. shottsii was named after the examination of 21 isolates recovered from
mycobacteriosis among striped in the Chesapeake Bay, USA (Rhodes et al. 2003 ).
The results of 16S rRNA sequencing linked the organisms to Mycobacterium ,
and bore some affi nity to Myc. marinum and Myc. ulcerans ( similarity = 99.2 %).
Box 3.13: Mycobacterium pseudoshottsii
Cultures develop rough colonies of 1–3 mm in diameter on Middlebrook 7H10
agar after incubation for 2 months at 23 °C, which slowly become pale yellow to
golden in the light, and comprise (clumping) acid-fast cocco-bacilli, which produce niacin and urease but not arylsulphatase, ß-galactosidase or pyrazinamidase, but do not reduce nitrates or attack Tween 80, and grow slightly at 30 °C not
at all at 37 °C. Resistance is recorded to 1 mg/ml of isoniazid. Cultures do not
grow on Löwenstein-Jensen medium or MacConkey agar (Rhodes et al. 2005 ).
Box 3.15: Mycobacterium shottsii
Comprises slow growing, non-pigmented acid fast aggregating cocco-bacilli
that grow at 23, less at 30 and none at all at 37 °C to produce small (0.5–
1.0 mm) rough fl at colonies becoming umbonate upon aging with slightly
irregular margins after 4–6 weeks on Middlebrook 7H10 agar, that produce
niacin and urease but not arylsulphatase, ß-galactosidase or pyrazinamidase,
do not reduce nitrate or attack Tween 80, and are resistant to isoniazid (1 μg/
ml) and p -aminosalicylic acid. Susceptibility is recorded to ethambutol, ethionamide, kanamycin, rifampicin and streptomycin. Growth does not occur on
Löwenstein Jensen medium or on MacConkey agar with 5 % (w/v) NaCl.
Mycolic acids are present, and comprise 8 peaks with similarities to the Myc.
tuberculosis complex (Rhodes et al. 2003 ).
Box 3.14: Mycobacterium salmoniphilum
Comprises acid fast slender, straight or slightly curved bacilli of 1–4 μm in
length and 0.25–0.6 mm in width that grow at 20–30 °C [weakly at 10 °C] on
blood agar, Löwenstein-Jensen agar, MacConkey agar and Middlebrook
7H10 agar producing smooth, shiny cream, colonies after 4–6 days. After
10 days incubation, colonies appear waxy with irregular edges [fried egg
appearance]. Growth does not occur at 37 °C. Arylsulphatase is positive, but
not so nitrate reduction (Whipps et al. 2007 ).
3 Aerobic Gram-Positive Rods and Cocci
Myc. pseudoshottsi (Rhodes et al. 2005 ).
Myc. salmoniphilum was revived as a valid species name (Whipps et al. 2007 ),
and has since been recognised as a cause of disease with mortalities in Norwegian
farmed Atlantic salmon, which displayed greyish-white nodules in the viscera
(Zerihun et al. 2011c ).
Myc. shottsii was named after the examination of 21 isolates recovered from
mycobacteriosis among striped in the Chesapeake Bay, USA (Rhodes et al. 2003 ).
The results of 16S rRNA sequencing linked the organisms to Mycobacterium ,
and bore some affi nity to Myc. marinum and Myc. ulcerans ( similarity = 99.2 %).
Box 3.13: Mycobacterium pseudoshottsii
Cultures develop rough colonies of 1–3 mm in diameter on Middlebrook 7H10
agar after incubation for 2 months at 23 °C, which slowly become pale yellow to
golden in the light, and comprise (clumping) acid-fast cocco-bacilli, which produce niacin and urease but not arylsulphatase, ß-galactosidase or pyrazinamidase, but do not reduce nitrates or attack Tween 80, and grow slightly at 30 °C not
at all at 37 °C. Resistance is recorded to 1 mg/ml of isoniazid. Cultures do not
grow on Löwenstein-Jensen medium or MacConkey agar (Rhodes et al. 2005 ).
Box 3.15: Mycobacterium shottsii
Comprises slow growing, non-pigmented acid fast aggregating cocco-bacilli
that grow at 23, less at 30 and none at all at 37 °C to produce small (0.5–
1.0 mm) rough fl at colonies becoming umbonate upon aging with slightly
irregular margins after 4–6 weeks on Middlebrook 7H10 agar, that produce
niacin and urease but not arylsulphatase, ß-galactosidase or pyrazinamidase,
do not reduce nitrate or attack Tween 80, and are resistant to isoniazid (1 μg/
ml) and p -aminosalicylic acid. Susceptibility is recorded to ethambutol, ethionamide, kanamycin, rifampicin and streptomycin. Growth does not occur on
Löwenstein Jensen medium or on MacConkey agar with 5 % (w/v) NaCl.
Mycolic acids are present, and comprise 8 peaks with similarities to the Myc.
tuberculosis complex (Rhodes et al. 2003 ).
Box 3.14: Mycobacterium salmoniphilum
Comprises acid fast slender, straight or slightly curved bacilli of 1–4 μm in
length and 0.25–0.6 mm in width that grow at 20–30 °C [weakly at 10 °C] on
blood agar, Löwenstein-Jensen agar, MacConkey agar and Middlebrook
7H10 agar producing smooth, shiny cream, colonies after 4–6 days. After
10 days incubation, colonies appear waxy with irregular edges [fried egg
appearance]. Growth does not occur at 37 °C. Arylsulphatase is positive, but
not so nitrate reduction (Whipps et al. 2007 ).
3 Aerobic Gram-Positive Rods and Cocci