鸡鲍氏志贺菌与痢疾志贺菌鸡白痢沙门菌及肠致病性大肠杆菌RAPD鉴别方法的建立

Establishment of random amplified polymorphic DNA assay for differentiation among Shigella boydii,Shigella dysenteriae,Salmonella pullorum and enteropathogenic Escherichia coli from chicken

利用随机扩增多态性DNA（RAPD）技术对鸡鲍氏志贺菌、鸡白痢沙门菌、肠致病性大肠杆菌和痢疾志贺菌的基因组DNA进行了研究，在此基础上分析了鸡鲍氏志贺菌与其他6个菌株的亲缘关系。结果显示，有4条随机引物的扩增多态性良好，共扩增出了64个DNA片段，其中4种菌共有的谱带有3条，而显示多态性的片段有61条，占95．3％。引物P2的扩增图谱不能将志贺菌和大肠杆菌鉴别开，但可将这2种菌与沙门菌鉴别出来；引物P6的扩增图谱清晰且3种菌间有明显差异，可用于上述3种细菌的鉴别。不同细菌间的遗传距离为0．128～0．790，根据遗传距离可将鸡鲍氏志贺菌等7个菌株分为3个聚类群，鸡鲍氏志贺菌分离株位于人痢疾志贺菌类群中，可能是人志贺菌的一个新的亚种。

Polymorphisms of the genomic DNA of Shigella boydii ,Salmonella pullorum, enteropathogenic Escherichia coli and Shigella dysenteriae from chicken were studied by random amplified polymorphic DNA（RAPD） assay. And genetic relationships among chicken S. boydii and other six bacterial strains were analyzed based on heredity distance. Four random primers were efficient to yield PCR product. Sixtyfour RAPD bands were identified and 3 of them were common in all four strains-tested,but 61 of them were polymorphic, and the polymorphic bands accounted for 95.3 %. The primer P2 could be used to differentiate Shigella and enteropathogenic E. coli from S. pullorum, but not be used to differentiate Shigella from enteropathogenic E. coli. The primer P6 could be used to differentiate the 3 species. Heredity distances among 7 bacterial strains were 0. 128-0. 790. According to the heredity distances,the 7 bacterial strains could be divided into 3 clustering groups, and chicken S. boydii and other two Shigella from human were in the same cluster group,which suggested that chicken S. boydii might be a new subspecies.