ABSTRAK

Penelitian ini bertujuan mengidentifikasi bakteri Aeromonas spp. penyebab penyakit MAS pada ikan lele melalui uji postulat Koch dan karakterisasi bakteri. Tujuh isolat bakteri (ANKII1, ANKII2, ANKII3, ANKIH1, ANKII4, ANKIG1, ANKIG2) diuji pada lele sehat menggunakan metode reinfeksi dengan tiga ulangan. Gejala klinis yang diamati meliputi perubahan tingkah laku, luka hemoragik, busuk sirip, pucat, dan kerusakan organ. Tingkat mortalitas berkisar 19,05%-47,62%, dengan isolat ANKIG1 menunjukkan mortalitas tertinggi (47,62%) dan rerata waktu kematian tersingkat. Semua isolat menunjukkan karakteristik Gram negatif dengan koloni bulat, berwarna krem-kuning, dan tepi halus. Parameter kualitas air tetap optimal selama penelitian. Hasil penelitian mengkonfirmasi Aeromonas spp. sebagai agen patogen penyebab penyakit MAS pada ikan lele, dengan isolat ANKIG1 paling virulen.

Kata kunci : Aeromonas spp., postulat Koch, ikan lele, mortalitas, identifikasi bakteri

ABSTRACT

This study aimed to identify Aeromonas spp. bacteria causing MAS disease in catfish through Koch's postulate test and bacterial characterization. Seven bacterial isolates (ANKII1, ANKII2, ANKII3, ANKIH1, ANKII4, ANKIG1, ANKIG2) were tested on healthy catfish using reinfection method with three replications. Clinical symptoms observed included behavioral changes, hemorrhagic lesions, fin rot, pale discoloration, and organ damage. Mortality rates ranged from 19.05% to 47.62%, with isolate ANKIG1 showing highest mortality (47.62%) and shortest mean time to death. All isolates showed Gram-negative characteristics with circular, cream-yellow colonies and smooth margins. Water quality parameters remained optimal throughout the study. Results confirmed Aeromonas spp. as pathogenic agents causing MAS disease in catfish, with isolate ANKIG1 being most virulent.

Keywords: Aeromonas spp., Koch's postulate,catfish, mortality, bacterial identification