In this study, we have for the first time isolated Aeromonas salmonicida strain XJ-JT from Yangtze finless porpoise which showed clinical symptoms such as ulcers and rotten skin. We found that the strain XJ-JT was a gram-negative bacterium with blunt ends and non-sporulating; 16S rRNA gene fragments of of several strains were amplified and sequenced, and phylogenetic trees were constructed which reveal the similarity with Aeromonas salmonicida isolated from Silver carp. Moreover, we studied its biological characteristics by performing physicochemical characterization, genetic evolution analysis, drug susceptibility assays and a pathogenicity test. 20 common antibiotics were tested in drug susceptibility assays. We showed that XJ-JT is highly sensitive to cefotaxime sodium,  ceftriaxone sodium and kanamycin, moderately sensitive to cefotaxime sodium, ceftriaxone sodium and kanamycin, and not sensitive to amoxicillin, ampicillin, tetracycline, and so on. An in vivo infection assay showed that this new strain, XJ-JT, has a strong pathogenicity in Crucian carp.

本文通过细菌的分离培养，首次从临床症状表现为溃疡、腐烂的患病江豚表皮分离到一株杀鲑气单胞菌XJ-JT株。通过细菌理化性质鉴定、遗传进化分析、药敏试验、致病性试验对其生物学特性进行分析，结果表明：菌株XJ-JT为革兰氏阴性短杆菌，两端钝圆，无芽孢；细菌分离鉴定的结果显示分离菌株为杀鲑气单胞菌；系统进化分析揭示其基因序列与银鲫源性杀鲑气单胞菌分离株高度同源；20种抗生素的药敏试验结果表明分离菌株对阿米卡星、克拉霉素、克林霉素等8种药物敏感，对头孢噻肟、头孢曲松、卡那霉素中介，对阿莫西林、氨苄西林、四环素等9种药物耐药；人工感染试验，结果显示分离菌对鲫鱼有较强的致病性。