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Isolation and molecular identification of the etiological agents of streptococcosis in Nile tilapia (Oreochromis niloticus) cultured in net cages in Lake Sentani, Papua, Indonesia.

Anshary H, Kurniawan RA, Sriwulan S, Ramli R, Baxa DV - Springerplus (2014)

Bottom Line: The latter species has not been previously isolated or reported from fish streptococcosis in Indonesia.Experimental infections and reisolation of the bacteria from morbid and dead fish suggest they are the causative agents of streptococcosis, which rendered high mortality among cage cultured Nile tilapia in Lake Sentani.Our results suggest the need for developing diagnostic tools for accurate identification of the agents of streptococcosis.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Fish Parasites and Diseases, Department of Fisheries, Faculty of Marine Science and Fisheries, Hasanuddin University, Makassar, Indonesia.

ABSTRACT
Infections with Streptococcus spp. were observed in Nile tilapia cultured in net cages in Lake Sentani, Papua, Indonesia. Clinical signs included exophthalmia, erratic swimming, ascites in abdominal cavity, and external hemorrhages. Four types of bacterial colonies (SK, K10, P20, and M12) were isolated from the brain, kidney, and eyes. Based on phenotypic and genetic (16S rDNA sequencing) characteristics, the isolates were identified as Streptococcus iniae (SK), Streptococcus agalactiae (K10 and P20) and Lactococcus garvieae (M12). The latter species has not been previously isolated or reported from fish streptococcosis in Indonesia. Intraperitoneal injection of healthy tilapia with the bacterial species caused significant morbidity (70%) within 3 days and 100% mortality at 6 days post injection. Experimental infections and reisolation of the bacteria from morbid and dead fish suggest they are the causative agents of streptococcosis, which rendered high mortality among cage cultured Nile tilapia in Lake Sentani. Our results suggest the need for developing diagnostic tools for accurate identification of the agents of streptococcosis. As tilapia aquaculture continues to expand as a means of food production and livelihood in Indonesia, it becomes crucial to ensure that fish resources are monitored and protected from the adverse effects of infectious diseases.

No MeSH data available.


Related in: MedlinePlus

Nile tilapia (Oreochromis niloticus) from Lake Sentani showing gross clinical signs of streptococcosis. a) exophthalmus, opaque, and haemorrhagic eye, b) pale gill, and c) ascites in abdominal cavity.
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Fig4: Nile tilapia (Oreochromis niloticus) from Lake Sentani showing gross clinical signs of streptococcosis. a) exophthalmus, opaque, and haemorrhagic eye, b) pale gill, and c) ascites in abdominal cavity.

Mentions: Tilapia (n = 25) with a total length of 15 to 25 cm and weight of 100 to 156 g with clinical signs including pop-eye/exophthalmia, pale gills, haemorrhage in eye, erratic and circular swimming were collected from floating net cages in Lake Sentani (Figure 4). The fish were put in three plastic bags containing water from the location and transported to the Laboratory of Molecular Biology, Fish Quarantine Inspection Agency (FQIA) Sentani, Jayapura. The floating net cage is a unit from which 25 nets were suspended. Each net (3 × 3 × 3 m) was stocked with 1,000 juvenile tilapia (15–25 g), and deployed in the eastern part of Lake Sentani, Papua, Indonesia (Figure 5). The farmers purchased the tilapia seeds from a local hatchery and cultured in the cages from 3–4 months to reach a weight of about 170 – 250 g. Moribund fish are frequently observed within 1 to 2 months of culture. The average water temperature in the morning was 28.5°C at the time of sampling. In the current survey, tilapia showing clinical signs were collected at 1 to 4 months post stocking.Figure 4


Isolation and molecular identification of the etiological agents of streptococcosis in Nile tilapia (Oreochromis niloticus) cultured in net cages in Lake Sentani, Papua, Indonesia.

Anshary H, Kurniawan RA, Sriwulan S, Ramli R, Baxa DV - Springerplus (2014)

Nile tilapia (Oreochromis niloticus) from Lake Sentani showing gross clinical signs of streptococcosis. a) exophthalmus, opaque, and haemorrhagic eye, b) pale gill, and c) ascites in abdominal cavity.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4216822&req=5

Fig4: Nile tilapia (Oreochromis niloticus) from Lake Sentani showing gross clinical signs of streptococcosis. a) exophthalmus, opaque, and haemorrhagic eye, b) pale gill, and c) ascites in abdominal cavity.
Mentions: Tilapia (n = 25) with a total length of 15 to 25 cm and weight of 100 to 156 g with clinical signs including pop-eye/exophthalmia, pale gills, haemorrhage in eye, erratic and circular swimming were collected from floating net cages in Lake Sentani (Figure 4). The fish were put in three plastic bags containing water from the location and transported to the Laboratory of Molecular Biology, Fish Quarantine Inspection Agency (FQIA) Sentani, Jayapura. The floating net cage is a unit from which 25 nets were suspended. Each net (3 × 3 × 3 m) was stocked with 1,000 juvenile tilapia (15–25 g), and deployed in the eastern part of Lake Sentani, Papua, Indonesia (Figure 5). The farmers purchased the tilapia seeds from a local hatchery and cultured in the cages from 3–4 months to reach a weight of about 170 – 250 g. Moribund fish are frequently observed within 1 to 2 months of culture. The average water temperature in the morning was 28.5°C at the time of sampling. In the current survey, tilapia showing clinical signs were collected at 1 to 4 months post stocking.Figure 4

Bottom Line: The latter species has not been previously isolated or reported from fish streptococcosis in Indonesia.Experimental infections and reisolation of the bacteria from morbid and dead fish suggest they are the causative agents of streptococcosis, which rendered high mortality among cage cultured Nile tilapia in Lake Sentani.Our results suggest the need for developing diagnostic tools for accurate identification of the agents of streptococcosis.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Fish Parasites and Diseases, Department of Fisheries, Faculty of Marine Science and Fisheries, Hasanuddin University, Makassar, Indonesia.

ABSTRACT
Infections with Streptococcus spp. were observed in Nile tilapia cultured in net cages in Lake Sentani, Papua, Indonesia. Clinical signs included exophthalmia, erratic swimming, ascites in abdominal cavity, and external hemorrhages. Four types of bacterial colonies (SK, K10, P20, and M12) were isolated from the brain, kidney, and eyes. Based on phenotypic and genetic (16S rDNA sequencing) characteristics, the isolates were identified as Streptococcus iniae (SK), Streptococcus agalactiae (K10 and P20) and Lactococcus garvieae (M12). The latter species has not been previously isolated or reported from fish streptococcosis in Indonesia. Intraperitoneal injection of healthy tilapia with the bacterial species caused significant morbidity (70%) within 3 days and 100% mortality at 6 days post injection. Experimental infections and reisolation of the bacteria from morbid and dead fish suggest they are the causative agents of streptococcosis, which rendered high mortality among cage cultured Nile tilapia in Lake Sentani. Our results suggest the need for developing diagnostic tools for accurate identification of the agents of streptococcosis. As tilapia aquaculture continues to expand as a means of food production and livelihood in Indonesia, it becomes crucial to ensure that fish resources are monitored and protected from the adverse effects of infectious diseases.

No MeSH data available.


Related in: MedlinePlus