170
Isolation
This is quite straightforward, involving use of kidney swabs with non-selective
media, such as nutrient agar or TSA, or selective media, namely Rimler-Shotts
medium (Appendix in Chap. 12 ; Shotts and Rimler 1973 ) or peptone beef-extract
glycogen agar (Appendix in Chap. 12 ; McCoy and Pilcher 1974 ) with incubation at
20–25 °C for 24–48 h. Typically, on non-selective media, cream, round, raised,
entire colonies of 2–3 mm diameter develop within 48 h at 25 °C.
Characteristics of the Pathogen
With improvements in the taxonomy of the “motile” aeromonads (see Carnahan and
Altwegg 1996 ), it is speculative about whether or not the fi sh isolates belong as Aer.
hydrophila or in any of the other Aeromonas Hybridisation Groups. To some extent,
Fig. 4.8 Aeromonas
infection in goldfi sh, which
is also displaying
abdominal swelling
(dropsy) and some surface
haemorrhaging
(Photograph courtesy of
Dr. A. Newaj-Fyzul)
Fig. 4.9 Generalised liquefaction of a rainbow trout associated with infection by Aeromonas
4 Aeromonadaceae Representatives (Motile Aeromonads)
Isolation
This is quite straightforward, involving use of kidney swabs with non-selective
media, such as nutrient agar or TSA, or selective media, namely Rimler-Shotts
medium (Appendix in Chap. 12 ; Shotts and Rimler 1973 ) or peptone beef-extract
glycogen agar (Appendix in Chap. 12 ; McCoy and Pilcher 1974 ) with incubation at
20–25 °C for 24–48 h. Typically, on non-selective media, cream, round, raised,
entire colonies of 2–3 mm diameter develop within 48 h at 25 °C.
Characteristics of the Pathogen
With improvements in the taxonomy of the “motile” aeromonads (see Carnahan and
Altwegg 1996 ), it is speculative about whether or not the fi sh isolates belong as Aer.
hydrophila or in any of the other Aeromonas Hybridisation Groups. To some extent,
Fig. 4.8 Aeromonas
infection in goldfi sh, which
is also displaying
abdominal swelling
(dropsy) and some surface
haemorrhaging
(Photograph courtesy of
Dr. A. Newaj-Fyzul)
Fig. 4.9 Generalised liquefaction of a rainbow trout associated with infection by Aeromonas
4 Aeromonadaceae Representatives (Motile Aeromonads)