جداسازی و شناسایی باکتری کرایزوباکتریوم آکواتیکوم (Chryseobacterium Aquaticum) از خوردگی باله‌ی دمی و زخم ساقه‌ی دمی ماهی قزل‌آلای رنگین‌کمان (Oncorhynchus Mykiss)

Some cultured rainbow trout (oncorhynchus mykiss) in a recirculating system farm showed caudal fin rot and peduncle erosion resulted in fish mortality. fish with peduncle erosion were collected and transferred in plastic bags with water to fish health laboratory unit. after washing with pbs, aseptic samples were taken from fish caudal peduncles. samples from liver and spleen of the fish were also collected. all samples were cultured both on nutrient as well as low nutrient media for bacterial isolations and examined up to 72h. bacterial isolates in this research was distinguished by physiological, biochemical and molecular tests. using pcr, the genotypic properties of the isolate were compared with similar isolates registered in the gene bank. results showed 99% phylogenetic similarity with a previously reported chryseobacterium aquaticum. this isolate showed resistance to most of conventional antibiotics. diseased fish were treated using potassium permanganate. reduction of fish population in each unit and improvement of the environmental condition for fish by adding more freshwater to the recirculation system were effective to control the disease.