647
and Ph. damselae subsp. piscicida , the use of media supplemented with blood aids
isolation.
However, the recovery of organisms on solid or in liquid media does not infer the
isolation of the pathogen causing the disease. A minimum requirement is that dense
growth should develop on the isolation plates. One, two or even three colonies types
should not be ignored as this situation could suggest infection by more than organism. It should be emphasised that the organisms recovered on bacteriological media
do not necessarily mean the instigator of the disease has been recovered. A microbial species succession could well occur with one organism instigating the infection, which may then be exacerbated by another. The possibility of secondary
invaders or contaminants/saprophytes should not be ignored. Yet, scant growth of a
diverse range of colony types does not suggest recovery of the actual pathogen.
Appendix – Media Used for the Isolation and Growth
of Bacterial Fish Pathogens
Anderson and Conroy’s Medium
for Sporocytophaga – Like Organisms
5.0 % (w/v) enzymic digest of fi sh muscle
0.1 % (w/v) peptone
0.1 % (w/v) yeast extract
0.9 % (w/v) agar
pH 7.0
This medium is prepared in seawater.
Blood and Serum Free Medium for Piscirickettsia salmonis
(Henriquez et al. 2013 )
0.5 % (w/v) glutamic acid
0.2 % (w/v) yeast extract
0.8 % (w/v) peptone from meat (peptic digested)
0.132 % (w/v) (NH 4 ) 2 SO 4
0.01 % (w/v) MgSO 4 .7H 2 O
0.63 % (w/v) K 2 HPO 4
0.9 % (w/v) NaCl
Appendix – Media Used for the Isolation and Growth of Bacterial Fish Pathogens
and Ph. damselae subsp. piscicida , the use of media supplemented with blood aids
isolation.
However, the recovery of organisms on solid or in liquid media does not infer the
isolation of the pathogen causing the disease. A minimum requirement is that dense
growth should develop on the isolation plates. One, two or even three colonies types
should not be ignored as this situation could suggest infection by more than organism. It should be emphasised that the organisms recovered on bacteriological media
do not necessarily mean the instigator of the disease has been recovered. A microbial species succession could well occur with one organism instigating the infection, which may then be exacerbated by another. The possibility of secondary
invaders or contaminants/saprophytes should not be ignored. Yet, scant growth of a
diverse range of colony types does not suggest recovery of the actual pathogen.
Appendix – Media Used for the Isolation and Growth
of Bacterial Fish Pathogens
Anderson and Conroy’s Medium
for Sporocytophaga – Like Organisms
5.0 % (w/v) enzymic digest of fi sh muscle
0.1 % (w/v) peptone
0.1 % (w/v) yeast extract
0.9 % (w/v) agar
pH 7.0
This medium is prepared in seawater.
Blood and Serum Free Medium for Piscirickettsia salmonis
(Henriquez et al. 2013 )
0.5 % (w/v) glutamic acid
0.2 % (w/v) yeast extract
0.8 % (w/v) peptone from meat (peptic digested)
0.132 % (w/v) (NH 4 ) 2 SO 4
0.01 % (w/v) MgSO 4 .7H 2 O
0.63 % (w/v) K 2 HPO 4
0.9 % (w/v) NaCl
Appendix – Media Used for the Isolation and Growth of Bacterial Fish Pathogens