牛源A型多杀性巴氏杆菌的分离鉴定及毒力基因检测

Isolation,identification and virulence gene detection of Pasteurella multocida capsular serotype A from bovine

为确定黑龙江省2个规模化奶牛场犊牛急性呼吸道感染的病因,笔者进行了病原的分离纯化,细菌16S rDNA基因和多杀性巴氏杆菌特异性基因OmpH鉴定、生化试验、药敏试验、半数致死量试验、荚膜血清型分型及22种毒力因子的检测,以确定主要病原的种类、型别及生物学特性。结果表明,从死亡牛肺和患病牛鼻拭子分离的2株病原菌均为荚膜A型多杀性巴氏杆菌,分别被命名为WC16551和LY01,序列分析结果表明,其与牛源多杀性巴氏杆菌同源性达到99%以上。药敏试验显示2株菌均对恩诺沙星、环丙沙星高度敏感。半数致死量结果表明,LY01菌株的毒力明显强于WC16551菌株,2株分离菌均携带19种毒力因子,未检出hgbB、toxA和nanB三种基因。上述研究结果表明,导致2个牛场发病的主要病原菌为荚膜A型多杀性巴氏杆菌。

In order to determine the pathogen on dairy farms in Heilongjiang Province,where cattles had respiratory-system diseases,the bacterial pathogen was isolated and purified.and these exprements that include the bacterial 16S rDNA gene,Pasteurella multocida specific gene Omp H identification,biochemical test,drug sensitivity test,median lethal dose test,capsular serotyping and 22 virulence factors detection were performed to identify the species,type and biological characteristics of major pathogens.In result,the two bacterial pathogens isolated from the dead bovine lung and the diseased bovine nasal swab were all Pasteurella multocida capsular Serotype A,named WC16551 and LY01.The sequence analysis showed that it was associated with Pasteurella multocida.The homology of bovine Pasteurella multocida was more than 99%.The susceptibility test showed that both strains were sensitive to enrofloxacin and ciprofloxacin.The half lethal dose showed that the LY01 toxicity was significantly stronger than WC16551.They all carry 19 virulence factors,three genes hgb B,tox A and nan B were not detected.The above-mentioned results showed that the main pathogen causing the onset on the two cattle farms is the capsular serotype A of Pasteurella multocida.