38
Use of Inhibitory Compounds
Erythromycin, dosed at 25 mg/kg body weight of fi sh/day for 4–7 days, controlled
streptococcicosis in yellowtail (Kitao 1982b ), and worked better than oxytetracycline or ampicillin (Shiomitsu et al. 1980 ). Doxycycline, at 20 mg/kg body weight
of fi sh/day for an unspecifi ed duration (Nakamura 1982 ), and josamycin, dosed at
30 mg/kg body weight of fi sh/day for 3 days (or dosed at 20 mg/kg body weight of
fi sh/day for 5 days) (Kusuda and Takemaru 1987 ; Takemaru and Kusuda 1988 ) have
also been advocated. It is of particular interest that a novel fi sheries therapeutant,
namely sodium nifurstyrenate dosed at 50 mg/kg body weight of fi sh/day for
3–5 days (Kashiwagi et al. 1977a , b ), has found use for streptococcicosis. This drug
appears to be particularly effective, and should not have problems with plasmidmediated resistance. The benefi ts of ionophores, namely lasalocid, monensin, narasin and salinomycin, were reported for an Enterococcus -like pathogen of rainbow
trout in Australia. Following a comparison of 40 isolates, it was noted that the MIC
of the ionophores was markedly less than erythromycin (0.1–0.8 μg/ml). Thus, the
MIC for lasalocid, monensin, narasin and salinomycin were 0.8 μg/ml, 0.4–1.5 μg/
ml, 0.2–04 μg/ml and 0.4–0.8 μg/ml, respectively. Perhaps, there are future opportunities for the use of some of these compounds in aquaculture.
The allocation of species names has sought to clarify the understanding of the
disease, and the following narrative will deal with the individual species.
Enterococcaceae Representatives
Enterococcus (Streptococcus) faecalis subsp. liquefaciens
Characteristics of the Disease
Although a question mark remains over the accuracy of the identifi cation of this
pathogen, its inclusion is justifi ed for the sake of completion. Also, this is the fi rst
indication of streptococci as fi sh pathogens in Croatia. Farmed brown bullhead
(Amiurus nebulosus) developed deep ulcers predominantly between the dorsal and
caudal fi ns, and there was haemorrhaging at the anus. Internal organs displayed
unspecifi ed changes, and fl uid was present in the digestive tract. Gram-positive
cocci were observed in the kidney and liver (Teskeredzic et al. 1993 ).
Characteristics of the Pathogen
We are not satisfi ed with the identifi cation of these isolates. However, in the absence
of an alternative, details from the original publication are included here (Teskeredzic
et al. 1993 ):
2 Gram-Positive Bacteria (Anaerobes and ‘Lactic Acid’ Bacteria)
Use of Inhibitory Compounds
Erythromycin, dosed at 25 mg/kg body weight of fi sh/day for 4–7 days, controlled
streptococcicosis in yellowtail (Kitao 1982b ), and worked better than oxytetracycline or ampicillin (Shiomitsu et al. 1980 ). Doxycycline, at 20 mg/kg body weight
of fi sh/day for an unspecifi ed duration (Nakamura 1982 ), and josamycin, dosed at
30 mg/kg body weight of fi sh/day for 3 days (or dosed at 20 mg/kg body weight of
fi sh/day for 5 days) (Kusuda and Takemaru 1987 ; Takemaru and Kusuda 1988 ) have
also been advocated. It is of particular interest that a novel fi sheries therapeutant,
namely sodium nifurstyrenate dosed at 50 mg/kg body weight of fi sh/day for
3–5 days (Kashiwagi et al. 1977a , b ), has found use for streptococcicosis. This drug
appears to be particularly effective, and should not have problems with plasmidmediated resistance. The benefi ts of ionophores, namely lasalocid, monensin, narasin and salinomycin, were reported for an Enterococcus -like pathogen of rainbow
trout in Australia. Following a comparison of 40 isolates, it was noted that the MIC
of the ionophores was markedly less than erythromycin (0.1–0.8 μg/ml). Thus, the
MIC for lasalocid, monensin, narasin and salinomycin were 0.8 μg/ml, 0.4–1.5 μg/
ml, 0.2–04 μg/ml and 0.4–0.8 μg/ml, respectively. Perhaps, there are future opportunities for the use of some of these compounds in aquaculture.
The allocation of species names has sought to clarify the understanding of the
disease, and the following narrative will deal with the individual species.
Enterococcaceae Representatives
Enterococcus (Streptococcus) faecalis subsp. liquefaciens
Characteristics of the Disease
Although a question mark remains over the accuracy of the identifi cation of this
pathogen, its inclusion is justifi ed for the sake of completion. Also, this is the fi rst
indication of streptococci as fi sh pathogens in Croatia. Farmed brown bullhead
(Amiurus nebulosus) developed deep ulcers predominantly between the dorsal and
caudal fi ns, and there was haemorrhaging at the anus. Internal organs displayed
unspecifi ed changes, and fl uid was present in the digestive tract. Gram-positive
cocci were observed in the kidney and liver (Teskeredzic et al. 1993 ).
Characteristics of the Pathogen
We are not satisfi ed with the identifi cation of these isolates. However, in the absence
of an alternative, details from the original publication are included here (Teskeredzic
et al. 1993 ):
2 Gram-Positive Bacteria (Anaerobes and ‘Lactic Acid’ Bacteria)