424
homogeneous group (Madsen and Dalsgaard 2000 : Madetoja et al. 2001 ; Valdebenito
and Avendaño-Herrera 2009 ), although two biovars have been identifi ed by use of
the API ZYM system (Hesami et al. 2009) although genetic diversity has been recognised (Chen et al. 2008; Del Cerro et al. 2010 ). Two distinct smooth, hydrophobic, adhesive (autoagglutinating) and rough (non-agglutinating) hydrophilic colony
phenotypes have been described (Högfors-Rönnholm and Wiklund 2010 ; Sundell
et al. 2013 ) with the smooth developing into the rough phenotype in broth, but never
the reverse. Both phenotypes were virulent to rainbow trout (Högfors-Rönnholm
and Wiklund 2010 ). Plasmid profi ling was carried out to evaluate genetic variability
among 104 isolates, most of which were recovered from Japan. Most (72/104 = 69 %)
possessed plasmids of 2.8, 3.4, 4.1 and 5.6 kb. The 3.4 kb plasmid was mostly
recovered from cultured obtained from rainbow trout; the 4.1 and 5.6 kb plasmids
were from Japanese isolates (Izumi and Aranashi 2004). The plasmid profi le may
refl ect the rough or smooth morphotype (Sundell et al. 2013 ).
The original 10 isolates of Pacha ( 1968 ) were deemed to be serologically homogeneous. Yet, later work identifi ed two major serogroups, with O-1 accommodating
isolates from Japan and the USA and O-2 comprising only Japanese cultures
(Wakabayashi et al. 1994 ). This number increased to three, with European isolates
included in one major serogroup (Lorenzen and Olesen 1997 ). Seven antigenic
types have been recognised among Finnish isolates, with results suggesting a new
serogroup (Madetoja et al. 2001 ). Furthermore, a novel serotype has been described
for cultures recovered from amago in Japan (Izumi et al. 2003). Several ribotypes
have been recognised among 85 isolates, with most harbouring one or more plasmids [11 plasmid profi les defi ned] (Chakroun et al. 1998 ). In comparison, 13 ribotypes were recognised among Finnish cultures (Madetoja et al. 2001 ). PCR and
Box 7.12: Flavobacterium psychrophilum
Cultures produce non-diffusible yellow-pigmented (fl exirubin pigment) colonies with thin spreading margins. Cells are strictly aerobic, Gram-negative,
slender, fl exible rods of 1.5–7.5 × 0.75 μm in size. With increasing age, the
cells appear to be shorter. As with Fla. hydatis, gliding movement is exhibited, and fruiting bodies and microcysts are absent. Catalase is produced, oxidase may appear to be positive, but H 2 S, indole, and lysine and ornithine
decarboxylase are not produced. Nitrates are not reduced, and the Voges
Proskauer reaction is negative. Casein, gelatin and tributyrin are degraded;
tyrosine is attacked by some isolates, and aesculin, chitin, starch and xanthine
not at all. Generally, growth occurs at 4–23 °C, but not at 30 °C, and in 0.8 %
but not 2 % (w/v) sodium chloride. This demonstrates clearly that the organisms are suited to low-temperature, freshwater environments. The organisms
are capable of degrading autoclaved cells of Esch. coli (Pacha 1968 ). The
G + C ratio of the DNA is 32.5–34 moles %.
7 Flavobacteria and Cytophagas
homogeneous group (Madsen and Dalsgaard 2000 : Madetoja et al. 2001 ; Valdebenito
and Avendaño-Herrera 2009 ), although two biovars have been identifi ed by use of
the API ZYM system (Hesami et al. 2009) although genetic diversity has been recognised (Chen et al. 2008; Del Cerro et al. 2010 ). Two distinct smooth, hydrophobic, adhesive (autoagglutinating) and rough (non-agglutinating) hydrophilic colony
phenotypes have been described (Högfors-Rönnholm and Wiklund 2010 ; Sundell
et al. 2013 ) with the smooth developing into the rough phenotype in broth, but never
the reverse. Both phenotypes were virulent to rainbow trout (Högfors-Rönnholm
and Wiklund 2010 ). Plasmid profi ling was carried out to evaluate genetic variability
among 104 isolates, most of which were recovered from Japan. Most (72/104 = 69 %)
possessed plasmids of 2.8, 3.4, 4.1 and 5.6 kb. The 3.4 kb plasmid was mostly
recovered from cultured obtained from rainbow trout; the 4.1 and 5.6 kb plasmids
were from Japanese isolates (Izumi and Aranashi 2004). The plasmid profi le may
refl ect the rough or smooth morphotype (Sundell et al. 2013 ).
The original 10 isolates of Pacha ( 1968 ) were deemed to be serologically homogeneous. Yet, later work identifi ed two major serogroups, with O-1 accommodating
isolates from Japan and the USA and O-2 comprising only Japanese cultures
(Wakabayashi et al. 1994 ). This number increased to three, with European isolates
included in one major serogroup (Lorenzen and Olesen 1997 ). Seven antigenic
types have been recognised among Finnish isolates, with results suggesting a new
serogroup (Madetoja et al. 2001 ). Furthermore, a novel serotype has been described
for cultures recovered from amago in Japan (Izumi et al. 2003). Several ribotypes
have been recognised among 85 isolates, with most harbouring one or more plasmids [11 plasmid profi les defi ned] (Chakroun et al. 1998 ). In comparison, 13 ribotypes were recognised among Finnish cultures (Madetoja et al. 2001 ). PCR and
Box 7.12: Flavobacterium psychrophilum
Cultures produce non-diffusible yellow-pigmented (fl exirubin pigment) colonies with thin spreading margins. Cells are strictly aerobic, Gram-negative,
slender, fl exible rods of 1.5–7.5 × 0.75 μm in size. With increasing age, the
cells appear to be shorter. As with Fla. hydatis, gliding movement is exhibited, and fruiting bodies and microcysts are absent. Catalase is produced, oxidase may appear to be positive, but H 2 S, indole, and lysine and ornithine
decarboxylase are not produced. Nitrates are not reduced, and the Voges
Proskauer reaction is negative. Casein, gelatin and tributyrin are degraded;
tyrosine is attacked by some isolates, and aesculin, chitin, starch and xanthine
not at all. Generally, growth occurs at 4–23 °C, but not at 30 °C, and in 0.8 %
but not 2 % (w/v) sodium chloride. This demonstrates clearly that the organisms are suited to low-temperature, freshwater environments. The organisms
are capable of degrading autoclaved cells of Esch. coli (Pacha 1968 ). The
G + C ratio of the DNA is 32.5–34 moles %.
7 Flavobacteria and Cytophagas