Identifikasi bakteri patogen Aeromonas sp. pada ikan Nila (Oreochromis niloticus) di Desa Matungkas, Kecamatan Dimembe, Kabupaten Minahasa Utara

The purpose of this study was to identify the bacteria Aeromonas sp. in a tilapia (Oreochromis niloticus) culture pond in Matungkas Village, Dimembe District, North Minahasa Regency. Bacterial identification was carried out at the Laboratory of the Fish Quarantine Center for Quality and Safety Control of Fishery Products, Manado. The time of the study was carried out from February 2021 - June 2021. Ten samples of fish were selected from 3 existing ponds for this study with the criteria of fish that have clinical signs of disease infection such as pale body surface, red spots and ulcers. From 10 samples, 19 isolates were obtained to be identified. The bacterial method was carried out based on the results of gram tests and biochemical tests which included: Gram Tests, Motility Test, Oxidase Test, Oxidative Fermentative Test, Tolerance Test to incubation temperature, Tolerance Test to pH of the media, Tolerance Test to the concentration of NaCl in the media and rimler – shotts selective media test. Of the 19 isolates from 10 samples identified, there were 7 isolates that were positive for A. hydrophila, namely: N1.4.1, N2.1.1, N2.1.2, N2.2.1, N2.3.2, N3.3.1, and N3.3.2. Twelve other isolates were negative for A. hydrophila. The characters of A. hydrophila identified are creamy in colour, gram negative, oxidase positive, bacteria tolerance to temperature 4 °C positive, 37 °C positive, 50 °C negative, can move (motile), fermentative, pH tolerance test media pH 3 negative, pH 5 positive, pH 9 positive, pH 11 positive, tolerance test for NaCl concentration 0.5% positive, 3% positive, 5% negative, rimler – shotts positive. All sampling sites (ponds) in Matungkas Village were infected with bacteria.