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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

Kaplan-Meier survival curve of Nile tilapia after challenge with the isolates:Streptococcus iniae(SK),S.agalactiae(K10, P20) andLactococcus garvieae(M12). Each fish was intraperitoneally injected with 0.1 ml of each bacterial suspension (1.0 × 107 CFU/mL mean density).
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Fig1: Kaplan-Meier survival curve of Nile tilapia after challenge with the isolates:Streptococcus iniae(SK),S.agalactiae(K10, P20) andLactococcus garvieae(M12). Each fish was intraperitoneally injected with 0.1 ml of each bacterial suspension (1.0 × 107 CFU/mL mean density).

Mentions: The four isolates that were phenotypically similar to S. iniae (SK), S. agalactiae (K10 and P20), and L. garvieae (M12) showed high pathogenicity to tilapia. Kaplan-Meier survival analysis showed that the mean survival time of tilapia injected with S. iniae, S. agalactiae and L. garvieae (0.1 ml of 1.0 × 107 CFU/mL) was 2.5, 1.83, and 3 days, respectively (Figure 1). All of the fish injected with each suspension of the bacterial isolate showed clinical signs and died within 6 days after injection. Morbidity or mortality was not observed in the control group while the bacteria were recovered from morbid and dead fish in the exposed injected groups.Figure 1


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)

Kaplan-Meier survival curve of Nile tilapia after challenge with the isolates:Streptococcus iniae(SK),S.agalactiae(K10, P20) andLactococcus garvieae(M12). Each fish was intraperitoneally injected with 0.1 ml of each bacterial suspension (1.0 × 107 CFU/mL mean density).
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Fig1: Kaplan-Meier survival curve of Nile tilapia after challenge with the isolates:Streptococcus iniae(SK),S.agalactiae(K10, P20) andLactococcus garvieae(M12). Each fish was intraperitoneally injected with 0.1 ml of each bacterial suspension (1.0 × 107 CFU/mL mean density).
Mentions: The four isolates that were phenotypically similar to S. iniae (SK), S. agalactiae (K10 and P20), and L. garvieae (M12) showed high pathogenicity to tilapia. Kaplan-Meier survival analysis showed that the mean survival time of tilapia injected with S. iniae, S. agalactiae and L. garvieae (0.1 ml of 1.0 × 107 CFU/mL) was 2.5, 1.83, and 3 days, respectively (Figure 1). All of the fish injected with each suspension of the bacterial isolate showed clinical signs and died within 6 days after injection. Morbidity or mortality was not observed in the control group while the bacteria were recovered from morbid and dead fish in the exposed injected groups.Figure 1

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