福建省产毒素多杀性巴氏杆菌的分离鉴定及致病性研究

Isolation, identification and pathogenicity of a toxin-producing Pasteurellamultocida

为探究2019年4月引起福建省南平市某猪场的育肥猪出现鼻塞、流鼻涕、呼吸时伴有鼾声、鼻梁弯曲变形等症状的病原,本研究通过采集30份发病猪的鼻腔拭子进行细菌分离纯化、鉴定以及采用特异性PCR对分离菌分型鉴定,同时分析其致病性。结果显示,从鼻腔拭子中分离出28株多杀性巴氏杆菌(Pm),分型PCR鉴定结果显示27株分离菌为荚膜D型产毒素多杀性巴氏杆菌(T^+Pm),1株分离菌为荚膜A型Pm,表明D型T+Pm为该次致猪发病的主要病原菌;利用特异性PCR方法对Pm进行脂多糖(LPS)基因型检测,鉴定结果显示该猪群感染的Pm LPS基因型全部为L6型;致病性实验结果显示该菌株能导致二元长白猪的肺脏呈熟肉样病变,病理组织切片显示有轻度水肿,少量炎性细胞浸润,伴少量散在出血。本研究获得的T+Pm对二元长白猪具有明显的致病性,为今后深入开展T+Pm致病机理、流行病学调查和防控技术的研究奠定了基础。

In order to investigate the pathogens causing symptoms of nasal congestion,runny nose,snoring and rhinoplasty in pigs from a pig farm in Nanping of Fujian province in April 2019.Isolation and identification were carried out by collecting samples of nasal swabs from infected pigs,and their types were identified and analyzed for pathogenicity by specific PCR methods.The results showed that 28 Pasteurellamultocida strains were isolated from the nasal swabs,and 27 of them were identified as capsular D-type toxin-producing Pasteurellamultocida and one asacapsular A-type Pasteurellamultocida by typing PCR.The lipopolysaccharide genotypes were detected by a specific PCR method for Pasteurellamultocida and the results showed that the genotypes of Pasteurellamultocida lipopolysaccharide infecting the pigs were all L6 type.Pathogenicity experiments showed that the isolate could cause the lungs of the binary hybrid Landrace pig to be cooked meaty lesions.Pathological sections showed mild edema,a small amount of inflammatory cell infiltration,with a small amout of scattered bleeding.The toxin-producing Pasteurellamultocida obtained in this study showed pronounced pathogenicity to binary Changbai hybrid pigs,and therefore our results laid a foundation for further research on the pathogenic mechanism,epidemiological investigation,and prevention and control technology of toxin-producing Pasteurellamultocida.