Kajian patogenisitas bakteri Edwardsiella ictaluri pada ikan patin Pangasionodon hypophthalmus Pathogenicity of Edwardsiella ictaluri infection in striped catfish Pangasionodon hypophthalmus

One of major problem of striped catfish Pangasionodon hypophthalmus culture is enteric septicemia of catfish (ESC), bacterial disease of Edwardsiella ictaluri, caused of more than 50% of mortalities. This reaserch was aimed to determine pathogenicity of local isolate E. ictaluri. Thirty individu of five group fishes, 6–10 g in body weight, injected intraperitoneally with 0,1 mL of bacteria suspension of 10 2 cfu/mL; 10 4 cfu/mL; 10 6 cfu/mL; 10 8 cfu/mL; 10 10 cfu/mL; and PBS as control, were culture in 18 of 60×40×45 cm 3 aquarium for seven days. External organs of fish (skin and abdomen) and internal organs (liver, kidney, and brain) were examined macroscopicly and microscopicly. Internal organ sample were taken on the 5 th day for histopatologic test while blood sample was on the 1 st , 3 rd , and 5 th day after infection. Mortality rate was count to reach LD50. Clinical signs and pathology anatomy of co-infection fish showed vertical swim, petechial hemorrhage in the skin, dropsy, ascites in the abdominal cavity, pale liver and the kidney was dark red. Histopathology showed hydropic degeneration, fatty degeneration, hemorrhage and necrosis in the liver, melano macrophage center (MMC) and necrosis in the kidneys, hemorrhage, and inflammatory cell infiltrates were also found in the kidneys and brain. Decreased of hematocrit and hemoglobin values of all tread group were statistically significant different (P<0,05) compared to controls. LD50 dose was 2,8×10 4 cfu/mL. The result indicated that E. ictaluri was very pathogenic on striped catfish P. hypophthalmus.