24株停乳链球菌似马亚种的分子鉴定和基因分型

目的 探讨停乳链球菌似马亚种(Streptococcus dysgalactiae subspecies equisimilis,SDSE)感染的临床分布特点及分子特征。方法 收集SDSE感染患者的临床资料及相应分离菌株,分离株经全自动微生物分析系统、基质辅助激光解析电离飞行时间质谱技术(MALDI-TOF-MS)及PCR扩增16S rRNA和链激酶前体基因等3种方-法进行鉴定。对SDSE菌株进行M蛋白基因(emm)分型和多位点序列分型(Multilocus sequence typing, MLST),并通过BioNumerics 6.6软件进行聚类分析。结果 24株停乳链球菌似马亚种主要分离自咽拭子、皮肤、血液,分别占58.33%、20.83%、8.33%;24株SDSE被分为5种emm类型,以stCNSRT2.0(n=16,66.7%)占优势,其次是stG840.0(n=3,12.5%)。通过MLST分型,共有6种ST型别,以ST44(n=17,70.8%)为主,ST605为新定义的ST型。结论 本研究中SDSE分离株具有分子多样性,ST605为首次报告的MLST型别。

Molecular identification and genotyping of 24 strains of Streptococcus dysgalactiae subspecies equisimilis

To explore the clinical distribution and molecular characteristics of Streptococcus dysgalactiae subspecies equisimilis (SDSE) infection, we collected clinical data and corresponding isolates from infected patients. The isolates were identified by three methods (automatic microorganism analysis system, MALDI-TOF-MS, and PCR amplification of 16S rRNA and the streptokinase precursor gene). emm typing and multilocus sequence typing of SDSE strains were performed, and BioNumerics 6.6 software was used for cluster analysis. A total of 24 strains of SDSE were isolated primarily from throat swab (58.33%), skin (20.83%) and blood (8.33%) samples. The strains were divided into five emm types, dominated by stCNSRT2.0 (n=16, 66.7%), which was followed by stG840.0 (n=3, 12.5%). Through MLST, six sequence types were distinguished, among which ST44 (n=17, 70.8%) was dominant, and ST605 was a newly discovered and defined sequence type, thus indicating the molecular diversity of SDSE isolates.