绵羊肺炎支原体不同分离株的致病性比较

Comparison of Pathogenicity of Different Mycoplasma ovipneumoniae Isolates

为研究不同绵羊肺炎支原体(Mycoplasma ovipneumoniae,Mo)的致病性差异,筛选出致病性强的Mo菌株。通过间接免疫荧光技术检测不同Mo分离株(XJ15、XJ13、XJ22、1412、XJN)、标准株(Y98)对山羊气管上皮细胞(goat tracheal epithelial cells,GTEC)的黏附力强弱,将不同Mo菌株以109 CCU/mL浓度,0.2 mL/只,接种到7日龄SPF鸡胚的卵黄囊中,设阴性对照组和空白对照组,检测并观察Mo感染鸡胚致死率以及死亡鸡胚病理变化,记录鸡胚死亡时间,取死亡鸡胚的尿囊液进行PCR鉴定,同时对各个感染组的卵黄囊液进行PCR检测。结果显示,6株Mo均能黏附GTEC细胞,其中XJ15黏附力最强,XJN黏附力最弱。在鸡胚感染试验中,6株Mo均能引起鸡胚死亡,且不同Mo感染组鸡胚死亡数差异显著(P<0.05)。其中,XJ15感染组致死率为90%,1412和XJN感染组致死率为20%。感染组死亡鸡胚表面有出血,充血症状,尿囊液PCR检测均为阳性。表明,筛选出XJ15为致病性较强的Mo分离株,为后期Mo人工感染模型的建立奠定基础。

In order to study the pathogenicity of different Mycoplasma ovipneumoniae(Mo),and screened out the Mo strains with high pathogenicity,in this study,the adhesions of different Mo isolates(XJ15,XJ13,XJ22,1412,XJN)and standard strain(Y98)to goat tracheal epithelial cells(GTEC)were detected by indirect immunofluorescence assay.The vitellicles of 7-day-old SPF chicken embryos were inoculated int o different Mo strains with the concentration of 109 CCU/mL,negative control group and blank control group were set.The mortality of infected chicken embryos and the pathological lesions of dead chicken embryos were detected and observed,the dead time of chicken embryos was recorded,the allantoic fluid and vitelline fluid of chicken embryos were taken for PCR.The results showed that all the six Mo strains could adhere to GTEC cells,XJ15 with the strongest adhesion and XJN with the weakest adhesion.In the experiment of chicken embryo infections,all six strains of Mo could cause chicken embryo death,and the numbers of chicken embryo death in different Mo infection groups were significantly different(P<0.05).The fatality rate of the XJ15 infection group was 90%,and that of the 1412 and XJN infection groups was 20%.In the infected group,there were bleeding and hyperemia on the surface of the dead chick embryos,and allantoic fluid was positive by PCR.In conclusion,XJ15 was screened as a highly pathogenic Mo strain in this study,which laid a foundation for further establishment of Mo artificial infection model.