356
Isolation
Pure culture growth was recovered from the heart, kidney and base of the lesions
following inoculation of nutrient agar, blood agar and TSA with incubation at
15–35 °C for an unspecifi ed period (Bejerano et al. 1979 ).
Characteristics of the Pathogen
Generally, the isolates matched the description of Pr. rettgeri (Cowan 1974 ;
Johnson et al. 1975 ; McKell and Jones 1976 ; Penner 2005 ).
Epizootiology
Inference was made that the source of infection was from poultry faeces, which
were used extensively to fertilise the carp ponds (Bejerano et al. 1979 ). In this connection, it is relevant to note that Pr. rettgeri has been associated with the digestive
tract of poultry.
Pathogenicity
Experimental infection of silver carp by i.m. injection of 5 × 10
2 bacteria, or by
scarifi cation of the fi sh surface and subsequent exposure to a broth culture, resulted
in mortalities of 50 % at a water temperature of 18–20 °C. Experimentally infected
fi sh showed lesions typical of the farmed stock (Bejerano et al. 1979 ).
Box 6.11: Providencia rettgeri
Cultures comprise fermentative Gram-negative rods, which are motile by
means of peritrichous fl agella. Catalase, indole, phenylalanine deaminase and
tryptophan deaminase are produced, but not β-galactosidase, H 2 S or oxidase.
DNA and urea are degraded, but not casein, gelatin, starch or the Tweens. The
methyl red test is positive. Nitrates are reduced. Acid is produced from adonitol, aesculin, erythritol, galactose, inositol, mannitol, mannose, melezitose,
rhamnose and salicin, but not from amygdalin, arabinose, cellobiose, dulcitol,
glycerol, glycogen, inulin, lactose, maltose, melibiose, raffi nose, ribose, sorbitol, sucrose, trehalose or xylose. The G + C ratio of the DNA is 39.2 moles
% (Bejerano et al. 1979 ).
6 Enterobacteriaceae Representatives
Isolation
Pure culture growth was recovered from the heart, kidney and base of the lesions
following inoculation of nutrient agar, blood agar and TSA with incubation at
15–35 °C for an unspecifi ed period (Bejerano et al. 1979 ).
Characteristics of the Pathogen
Generally, the isolates matched the description of Pr. rettgeri (Cowan 1974 ;
Johnson et al. 1975 ; McKell and Jones 1976 ; Penner 2005 ).
Epizootiology
Inference was made that the source of infection was from poultry faeces, which
were used extensively to fertilise the carp ponds (Bejerano et al. 1979 ). In this connection, it is relevant to note that Pr. rettgeri has been associated with the digestive
tract of poultry.
Pathogenicity
Experimental infection of silver carp by i.m. injection of 5 × 10
2 bacteria, or by
scarifi cation of the fi sh surface and subsequent exposure to a broth culture, resulted
in mortalities of 50 % at a water temperature of 18–20 °C. Experimentally infected
fi sh showed lesions typical of the farmed stock (Bejerano et al. 1979 ).
Box 6.11: Providencia rettgeri
Cultures comprise fermentative Gram-negative rods, which are motile by
means of peritrichous fl agella. Catalase, indole, phenylalanine deaminase and
tryptophan deaminase are produced, but not β-galactosidase, H 2 S or oxidase.
DNA and urea are degraded, but not casein, gelatin, starch or the Tweens. The
methyl red test is positive. Nitrates are reduced. Acid is produced from adonitol, aesculin, erythritol, galactose, inositol, mannitol, mannose, melezitose,
rhamnose and salicin, but not from amygdalin, arabinose, cellobiose, dulcitol,
glycerol, glycogen, inulin, lactose, maltose, melibiose, raffi nose, ribose, sorbitol, sucrose, trehalose or xylose. The G + C ratio of the DNA is 39.2 moles
% (Bejerano et al. 1979 ).
6 Enterobacteriaceae Representatives