福氏志贺菌PFGE和MLVA分子分型方法的应用与评价

目的 比较和评价脉冲场凝胶电泳技术(PFGE)和多位点可变数目串联重复序列分析技术(MLVA)在福建地区福氏志贺菌研究中的应用。方法 运用PFGE和MLVA技术对43株分离自福建地区的福氏志贺菌进行分子分型,结合流行病学资料分析比较分型效果。结果 43株福氏志贺菌经PFGE分型后相似度在61.70%~100%之间,按照100%的相似水平可分为36个PFGE型,没有优势PFGE型别,分辨系数为0.992 2,存在4个优势簇(G1~G4);福氏志贺菌经MLVA分型后,按照100%的相似水平可分为41个MLVA型别,遗传关联度介于6.207％～100％之间,没有优势MLVA型别,分辨系数为0.997 8,得到5个优势基因群(Cluster1~5)。在最小生成树上,部分F4c与Fx亲缘关系较近,并都由F2a和F1a分支而来,表现出一定的遗传关系。结论 两种分型方法的分辨率基本一致,PFGE分型结果与流行病学背景资料及血清型别基本吻合,MLVA在分析菌株种群进化关系上更具优势。

Application and assessment of PFGE and MLVA molecular typing on Shigella flexneri

In order to compare and evaluate pulse field gel electrophoresis (PFGE) and multiple locus VNTRs analysis (MLVA)　on the molecular typing of Shigella flexneri in Fujian Province. Totally 43 strains of Shigella flexneri were genotyped by PFGE and MLVA, and the results were compared with epidemiological data. The results indicated that the similarity coefficient among the 43 isolates was from 61.70 %to 100% by PFGE with D index value of 0.9922, which could be divided into 36 PFGE types according to the 100% similarity with no advantage one, but there were 4 dominant groups (G1-G4); while MLVA produced 41 types, the similarity coefficient among which was 6.207％-100％ with D index value of 0.9978 and no advantage type, but there were also 5 dominant clusters. In the minimum spanning tree, some strains of F4c were close to Fx, and they all came from F2a and F1a, which show a certain genetic relationship. All the results suggest the discriminatory ability of the two methods is roughly the same. The typing result of PFGE is consistent with the epidemiological data and serotype, and MLVA has an advantage in analyzing the evolutionary relationship of bacterial strains.