16S rDNA测序鉴定β溶血性G群链球菌

Identifying Group G β-hemolytic Streptococci Strains by 16S rDNA Sequencing

目的对一起群聚性儿童肾小球肾炎暴发事件中分离到的26株β溶血性G群链球菌进行16SrDNA测序鉴定,探讨该方法在病原学鉴定方面的意义。方法分别采用API20 Strep生化鉴定系统、部分和全序列测定16S rDNA鉴定26株β溶血性G群链球菌;使用MegaV3.1软件,采用Neighbour-joining方法和boot-strap test对部分菌株的全序列进行树状图分析。结果API20 Strep生化鉴定率低,未能鉴定出目的菌;采用16S rDNA测序,结果均为咽峡炎链球菌(S.anginosus),鉴定率大于97%。其中4株G群的全序列树状图分析显示,G群链球菌均与咽峡炎链球菌聚类在同一簇。结论16S rDNA序列鉴定能提供详细明确的核苷酸信息,能区分G群链球菌不同的种,显示其在菌株鉴定方面的独特优势。

Objective To identify the DNA sequences of 26 beta-hemolytic group G streptococci strains isolated from the swabs of patients in a glomerulonephritis outbreak event. Methods API20 Strep system and 16S rDNA sequencing were performed on a11 of the 26 isolated strains respectively. The dendrogram based on the analysis of the 16S rDNA sequences of four groups of G streptococci strains was constructed by the neighbor- joining method and boot-strap test. Results The API20 Strep system failed to identify the strains with less than 62% of success rates. All of the 26 group G beta-hemolytic streptococci isolates were identified as Streptococcus anginosus by the 16S rDNA sequencing, with more than 97% of success rates. The dendrogram illustrated that the four groups of G streptococci strains were clustered at the same branch with Streptococcus anginosus. Conclusion The 16S rDNA sequencing has unique advantages over the phenotypic methods. It can provide detailed information of nucleotides and identify species of beta-hemolytic G group streptococci.