Isolasi Aeromonas jandaei dan Bakteriofag dari Kolam Budi Daya Nila (Oreochromis sp.) di Kabupaten Sleman

Nabil Ghifari Abdillah, Indah Istiqomah, S.Pi., M.Si., Ph.D

2026 | Skripsi | BUDIDAYA PERIKANAN

Penelitian ini bertujuan untuk mengisolasi Aeromonas jandaei dan bakteriofag dari kolam budi daya ikan nila di Kabupaten Sleman. Isolat bakteri diperoleh dari ginjal ikan Nila yang menunjukkan gejala MAS. Bakteri diisolasi pada media selektif GSP (Glutamate Strach Phenol). Karakterisasi bakteri dilakukan melalui uji KOH 3%, uji katalase, uji oksidase dan pewarnaan Gram. Identifikasi secara molekuler menggunakan gen gyrase B, serta uji LD50. Isolasi bakteriofag dilakukan menggunakan sampel air kolam tempat ikan terinfeksi MAS dengan proses enrichment, plaque assay, pemurnian, pengamatan morfologi menggunakan TEM (Transmission Electron Microscopy), uji kisaran inang (host range), dan uji daya hambat pertumbuhan bakteri. Hasil penelitian menunjukkan bahwa isolat bakteri yang telah diisolasi merupakan bakteri Gram negatif berbentuk batang, dengan katalase positif, dan oksidase positif. Hasil analisis sekuens gen gyrase B menggunakan BLAST menunjukkan tingkat similaritas 100% terhadap Aeromonas jandaei. Nilai LD50 yang diperoleh sebesar 4,17 x 105 CFU/mL. Isolasi bakteriofag menghasilkan titer awal sejumlah 6,55 x 106 PFU/mL dan titer pemurnian sejumlah 9,17 x 102 PFU/mL. Pengamatan TEM menunjukkan morfologi virion berbentuk ikosahedral dengan diameter kapsid 88,11 nm dengan ekor sepanjang 134,02 nm yang diduga menyerupai anggota famili Myoviridae. Hasil uji kisaran inang menunjukkan bahwa bakteriofag hanya mampu melisiskan isolat Aeromonas jandaei sebagai inang utama. Pada uji daya hambat, bakteriofag menunjukkan kemampuan menghambat pertumbuhan bakteri hingga jam ke-6 selama masa inkubasi. Penelitian ini berhasil mengisolasi dan mengkarakterisasi Aeromonas jandaei serta memperoleh bakteriofag yang bersifat spesifik terhadap bakteri tersebut. Hasil penelitian menunjukkan potensi bakteriofag sebagai agen biokontrol terhadap Aeromonas jandaei pada budi daya ikan nila.

This study aimed to isolate Aeromonas jandaei and its bacteriophages from Nile tilapia (Oreochromis sp.) culture ponds in Sleman Regency. The bacterial isolate was obtained from the kidneys of Nile tilapia exhibiting clinical signs of Motile Aeromonas Septicemia (MAS). The bacteria were isolated on GSP (Glutamate Starch Phenol) selective medium. Bacterial characterization was performed using the 3% KOH test, catalase test, oxidase test, and Gram staining. Molecular identification was carried out by amplification and sequencing of the gyrase B gene, followed by determination of the median lethal dose (LD??). Bacteriophages were isolated from pond water collected from ponds containing MAS-infected fish through an enrichment process, plaque assay, purification, morphological observation using Transmission Electron Microscopy (TEM), host range determination, and bacterial growth inhibition assay. The results showed that the bacterial isolate was a Gram-negative, rod-shaped bacterium that was catalase-positive and oxidase-positive. BLAST analysis of the gyrase B gene sequence revealed 100% similarity to Aeromonas jandaei. The LD?? value was determined to be 4.17 × 10? CFU/mL. Bacteriophage isolation yielded an initial titer of 6.55 × 10? PFU/mL and a purified phage titer of 9.17 × 10² PFU/mL. TEM observations revealed an icosahedral virion with a capsid diameter of 88.11 nm and a tail length of 134.02 nm, suggesting morphological characteristics similar to members of the family Myoviridae. The host range assay demonstrated that the bacteriophage specifically lysed Aeromonas jandaei as its primary host. In the bacterial growth inhibition assay, the bacteriophage inhibited bacterial growth for up to 6 hours during the incubation period. This study successfully isolated and characterized Aeromonas jandaei and obtained a bacteriophage with high specificity toward this bacterium. The findings indicate that the isolated bacteriophage has potential as a biological control agent against Aeromonas jandaei in Nile tilapia aquaculture.

Kata Kunci : Aeromonas jandaei, bakteriofag, ikan nila, dan MAS