Isolasi Dan Karakterisasi Bakteri Edwardsiella tarda Penyebab Penyakit Pada Ikan Air Tawar

EKA DINIARTI, Dr.Ir. Murwantoko,M.Si.,

2013 | Skripsi | BUDIDAYA PERIKANAN

Penelitian ini bertujuan untuk mengisolasi dan karakterisasi bakteri Edwardsiella tarda penyebab penyakit pada ikan air tawar, serta patogenisitasnya terhadap ikan patin (Pangasius sutchi). Bakteri diisolasi dari bagian ginjal ikan pada medium TSA (Tryptone Soya Agar) dan dikarakterisasi morfologi koloni, morfologi sel dan sifat biokimianya. Uji Postulat Koch dilakukan dengan penyuntikan intraperitoneal isolat E. tarda terhadap ikan lele (Clarias sp.) dan nila (Oreochromis sp.) ukuran 7-9 cm pada dosis 107CFU/ikan. Uji patogenisitas dilakukan terhadap E. tarda dengan penyuntikan intraperitoneal pada ikan patin ukuran 7-9 cm dengan dosis 104, 105, 106, dan 107 CFU/ikan dan dilakukan pengamatan kematian ikan setiap enam jam, selama 7 hari. Patogenisitas bakteri ditentukan berdasarkan pada nilai Lethal Dosage 50 (LD50) yang dihitung menggunakan metode Dragstedt Behrens. Penelitian telah memurnikan 33 isolat dan tiga isolat diantaranya merupakan Edwardsiella tarda penyebab penyakit pada ikan. Gejala penyakit akibat serangan bakteri ini berupa kulit ikan mengalami kehilangan pigmen warna, pucat dan mengelupas, lambung membengkak, luka haemoragik pada anus, lesi kecil putih pada tubuh dan terjadi nekrosis pada sirip. Nilai Lethal Dosage 50 (LD50) E. tarda isolat L2, L3, dan N3 masing-masing sebesar (4,64±0,35)x105, (1,54±0,07)x105, dan (1,13± 0,13) x106 CFU/ikan.

This study was conducted to isolate and characterize Edwardsiella tarda as causative disease of freshwater fishes, and its pathogenicity to catfish (Pangasius sutchi). Bacteria were isolated from the kidney on Trypticase Soya Agar (TSA) medium and followed by morphological colonies, morphological cells and biochemical tests. Koch postulate was conducted by intraperitoneal injection of E. tarda isolates to catfish (Clarias sp.) and tilapia (Oreochromis sp.) with 7-9 cm of total lenght at 107 CFU/fish. Pathogenicity test of E. tarda was carried out by intraperitoneal injection at 104, 105, 106, and 107 CFU/fish to catfish at 7-9 cm of total lenght and followed by observation of disease signs and mortality was every in six hours for 7 days. Pathogenicity of E. tarda was determinated with Lethal Dosage (LD50) which was calculated by Dragstedt Behrens method. This research have purified 33 isolates and three of them were E. tarda causing disease in fishes. The clinical signs of this disease are lose of pigmentation over the lession, swollen of stomach, haemorhage on fin, small cutaneous lesions, and necrotic on fins area. Infection of the pathogenic E. tarda caused acute mortality within 24-30 hour. Dosage ( LD50 ) of E. Tarda L2, L3, and N3 each were (4,64 ± 0,35) x105, (1,54 ± 0,07) x105, and (1,13 ± 0,13) x106 CFU/fish.

Kata Kunci : Edwardsiella tarda, Postulat Koch, Patogenisitas, patin (Pangasius sutchi)