关键词: 齐口裂腹鱼, 溃疡病, 嗜水气单胞菌, 分离, 鉴定

Abstract: A highly pathogenic pathogen D060501 was isolated from the diseased Schizothorax prenanti with typical skin ulcer, and animal experiments confirmed that the bacteria can cause obvious surface ulcer disease on health Schizothorax prenanti and have a strong pathogenic effect.Through the apparent taxonomic identification of morphological, physiological and biochemical characteristics, the bacteria strains were grown smooth edges and shiny circular white colonies with haemolyticus.The staining found the bacteria were Gram-negative brevibacterium with the features of the mobility, fermentation of glucose, lipase, oxidase and arginine double-hydrolase positive reaction, making use of glucose to produce gas, arabinose to produce acid, sulfureted hydrogen, potassium cyanide and V-P positive reaction, negative reaction of DNA enzymes and urea.The 16S rDNA of the bacteria was amplified, cloned and sequenced, a length of 1 514 bp nucleotide sequence were obtained, which were Blast in GenBank and downloaded the high homology bacterial sequence, then the sequences were aligned, analyzed and constructed the phylogenetic tree.The results showed that D060501 and other Aeromonas hydrophila(Genbank accession number AF468055) forms a cluster and have the closest relationship with the 99.1% homology.According to the phylogenetic tree, the evolutionary distance between D060501 strain and other seven strain is less than 1.0 and it can be identified as Aeromonas hydrophila based on its morphological and physiological characteristics.Sensitive test of the bacteria showed that the strain highly sensitive to chloramphenicol and gentamicin but resist to tetracycline, cotrimoxazole, doxycycline and carbenicillin.

Key words: Schizothorax prenanti, skin ulcer, Aeromonas hydrophila, isolation, identification