STUDI PATOGENISITAS DAN MOLEKUL ISOLAT Edwardsiella tarda PADA UKAN AIR TAWAR DI INDONESIA

The aim of this study was to determine a). The concentration of LC 50 of E. Tarda from tilapia fish (Oreochromis niloticus) in Yogyakarta, Mas fish (Cyprinus carpio) in Pontianak, fish Catfish (Clarias batrachus) in Semarang and Lumajang, as well as import Turtles dar Brasilia. b). Pathogenicity of isolates of E. tarda from tilapia fish (Oreochromis niloticus) in Yogyakarta, including clinical symptoms, blood picture and pathological changes. c). The existence of variations in isolates of E. tarda from several locations in Indonesia by molecular (PCR-RFLP and phylogeny). Isolates E. tarda were taken from Tilapia (Yogyakarta), catfish (Semarang and Lumajang), Imported Tortoise (Brazil), goldfish (Pontianak). After the revirulence process was tested by lethal concentration (LC50) in tilapia, catfish, chef, Celebes rainbow, and carp. Pathogenicity test was performed by interesting on tilapia by isolates of E. tarda from Yogyakarta. Observations were conducted in clinical symptoms, macroscopic and histopathological changes. Atypical isolates of E. tarda (ATCC) imported from Singapore was used as the standart is a comparison 4 isolates of E. tarda from Indonesia. All isolates of E. tarda were be extracted, Small Sub Unit RNA gen (SSU RNA gene), was amplified and digested with HaeIII and AluI enzymes, sequenced for phylogenetic tree. The isolation and identification results from 4 isolates showed similar results to isolates ATCC. LC50 test showed that isolates of E. tarda from Pontianak was the most pathogens is 1.8 x 105 cells/ml for 6 days. Generally, the Clinical symptoms were similar in all the fish such as anorexia, slow swimming, redness of the skin lesions and base of the fin. Tissue lesions skin began to appear on the two day post infection of the organ, the more widespread occurred on day 14 post infection. Total number of leukocytes and increased heterophile obvious at day 11 post infection E. tarda in tilapia. Three isolates of E. tarda from Pontianak, Jambi, Yogyakarta was same strain originating from fish, whereas the isolates of E. tarda from turtle was identical strain with ATCC isolates from human origin