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

Siti Narwiyani, Ir.,MP., Prof. drh. Kurniasih, M.V.Sc., Ph.D

2012 | Disertasi | S3 Sain Veteriner

Penelitian ini bertujuan untuk mengetahui a). perbedaan patogenisitas isolat Edwardsiella tarda yang berasal dari berbagai daerah dan jenis ikan,b). adanya kemungkinan variasi E. tarda secara molekuler, c). adanya perubahan pertahanan tubuh non spesifik pada ikan terinfeksi E. tarda, d). hubungan antara variasi genetik dan tingkat patogenisitas. Isolat E. tarda diperoleh dari ikan Nila (Yogyakarta), Lele (Semarang dan Lumajang), Kura-kura impor (Brazilia), ikan Mas (Pontianak). Sesudah proses revirulensi semua isolat kemudian dilakukan uji lethal concentration (LC50) pada ikan Nila, Patin, Koki, Celebes rainbow, dan Mas. Uji patogenesitas dilakukan pada ikan Nila yang diinfeksi dengan isolat E. tarda yang berasal dari Yogyakarta. Pengamatan dilakukan terhadap gejala klinis, perubahan makroskopik dan histopatologi. Isolat atipikal E. tarda (ATCC) dari Singapura digunakan sebagai pembanding 4 isolat E. tarda dari Indonesia. Semua isolat E. tarda di ekstraksi, diamplifikasi pada Small Sub Unit RNA gen (SSU RNA gen), didigesti dengan enzim HaeIII dan AluI, disequensing untuk uji phylogenetic tree. Hasil isolasi dan identifikasi dari 4 isolat menunjukkan hasil yang sama dengan isolat ATCC. Uji LC50 menunjukkan bahwa isolat E. tarda yang berasal dari Pontianak yang paling patogen yaitu 1,8 x 105 sel/ml selama 6 hari. Gejala klinis umumnya sama pada semua ikan berupa anoreksia, berenang lambat, lesi kemerahan pada kulit dan pangkal sirip. Lesi jaringan kulit mulai tampak pada hari kedua, makin meluas pada hari ke 14 sesudah infeksi. Jumlah leukosit total dan heterofil meningkat jelas pada hari ke 11 sesudah infeksi E. tarda pada ikan Nila. Tiga isolat E. tarda dari Pontianak, Jambi, Yogyakarta adalah strain yang sama berasal dari ikan, sedangkan isolat E. tarda dari kura-kura merupakan strain yang sama dengan isolat ATCC berasal dari manusia

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.

Kata Kunci : Patogenesitas, molekuler, Edwarsiella tarda