一株鸭源维氏气单胞菌的分离鉴定与致病性的初步研究

Isolation and identification of Aeromonas veronii from duck and preliminary study on its pathogenicity

江苏某养殖场种鸭突然发生散发性死亡,为了探究其死亡原因,本研究通过临床解剖观察、病原分离、生化试验、药敏试验、雏鸭人工感染试验和致病性试验对分离菌株进行检测。结果显示该分离菌为革兰阴性短杆菌,在麦康凯培养基和LB培养基中呈现圆形灰白色菌落,在血琼脂培养基中呈现出β溶血;16S rRNA基因序列分析结果显示该菌为维氏气单胞菌(A.veronii);药敏结果显示该菌对头孢氨苄、氨苄西林等10种抗生素敏感;人工感染试验显示该菌可造成雏鸭的死亡;小鼠的致病性试验显示该菌对小鼠的LD50为5.0×10^6.5cfu。总之,本实验从病鸭中分离到1株A.veronii,并筛选出敏感药物,为A.veronii病的诊断和治疗提供了参考依据。

To explore the pathogenic agent that caused sudden sporadic death of breed ducks from a farm in Jiangsu province the pathogen was isolated and identified based on clinical autopsy observation,the biochemical assay,16S rRNA sequence analysis drug sensitivity test,duckling artificial infection test and its pathogenicity in mice.The results showed that a suspected strain was identified as gram-negative short bacillus,showing round grey-white colonies in MacConkey agar medium and LB agar medium and betahemolysis in blood agar medium,and the bacterium was confirmed as Aeromonas veronii by the 16S rRNA gene sequence analysis.The drug sensitivity test indicated that the isolate was sensitive to ten kinds of antibiotics including cephalexin and ampicillin.Artificial infection test showed that the isolate can cause the death of duckling.The pathogenicity of the isolate indicated that the LD50 of Aeromonas veronii was 5.0×10^6.5 cfu in mice.In summary,one strain of Aeromonas veronii was successfully isolated and identified from the diseased duck in our study,and the sensitive drugs were screened,providing a reference for the diagnosis and treatment of Aeromonas veronii disease.