獭兔巴氏杆菌的分离鉴定及抑菌作用分析

Isolation,identification and bacteriostatic analysis of Pasteurella in Rex rabbits

为了确定引起南昌某兔场獭兔发病的病原,并找到有效的防治措施,试验对病死獭兔进行了临床诊断、细菌分离、生化鉴定、16S rRNA分子生物学鉴定、药敏试验、体外抑菌试验及动物回归试验。结果表明:剖检可见肝脏上有针尖状白色坏死点,分离菌瑞氏染色镜检呈两极浓染;菌落在5%兔血琼脂培养基上呈现圆润不溶血现象,为革兰氏阴性短小杆菌;分离菌均能发酵蔗糖,不能发酵乳糖,甲基红、乙酰甲基甲醇试验呈阴性;琼脂糖凝胶电泳得到大小为1 800 bp的目的条带,分离菌与NCBI中巴氏杆菌属的同源性高达97.3%~100%;分离菌对头孢氨苄高度敏感,对乙酰螺旋霉素和氨苄西林耐药;鸡唾液乳杆菌对分离菌的抑制效果较好;分离菌有较强的致病性,攻毒后12 h内小鼠全部死亡。说明分离菌为巴氏杆菌,防治首选头孢曲松或头孢氨苄。

In order to determine the pathogenic factors of Rex rabbit in Nanchang rabbit farm and to find effective prevention and control measures, the experiment carried out clinical diagnosis, bacterial isolation, biochemical identification, 16 S rRNA molecular biology identification, drug sensitivity test, in vitro antibacterial test and animal regression test on dead Rex rabbits. The results show that there were needle-shaped white necrotic spots on the liver on autopsy and Wright’s staining microscopic examination showed two-pole dense staining. The colony showed roundness and non-hemolysis on 5% rabbit blood agar medium, and it was Gram-negative short bacillus. The isolated bacteria can ferment sucrose, but not lactose. The methyl red and acetyl methyl methanol tests were negative. Agarose gel electrophoresis obtained a band of 1 800 bp in size, and the homology between the isolate and Pasteurella in NCBI was as high as 97.3%-100%. The isolate was highly sensitive to ceftriaxone, and was resistant to acetylspiramycin and ampicillin. Ligilactobacillus salivarius had good inhibitory effect on the isolate. The isolate was highly pathogenic, and all mice died within 12 hours after the challenge. The results suggested that the isolate was Pasteurella,and ceftriaxone or cephalexin were the first choice for prevention and treatment.