应用核酸杂交Ribotyping技术对B组链球菌的研究

Genetic Characteristics of Group B Streptococcus by Southern Blot and Ribotyping

目的 了解 B组链球菌 (GBS)菌株致病毒力因子和基因型分布特点 ,探讨 Ribotyping技术在 GBS菌株基因分型中的应用价值。 方法 应用核酸杂交和 16 Sr RNA基因广谱基因探针杂交 (Ribotyping)方法 ,对妊娠妇女阴道拭子分离所获 34株 GBS菌进行分析。 结果 34株 GBS均含有 scaa、scp B、gln A基因 ;所有 GBS血清型 、 / C型有 bac和 bca基因 ,6 0 % GBS- Ia型无 bac和 bca基因 ,而血清型 、 / R型无 bac和 bca基因 ;三种内切酶 (Hind 、Eco RI、Pvu )结合分析 ,34株GBS共产生 16个独特 Ribotyping基因型 ;将 Ribotyping与核酸杂交两种分子生物学方法结合分析 ,34株 GBS共产生 2 2个基因型。 结论 Ribotyping方法具有分型率和分辨力高 ,稳定性强 ,重复性好和谱型易于分析特点 ,在 GBS分型和流行病学研究中具有应用价值。将两种以上基因分型方法结合更具有潜在的使用价值。

Objectives To evaluate typing value by ribotyping technique for detection DNA of group B streptococcus( GBS) strains, to obtain the genotypes and genetic characteristics. MethodsThirty four GBS strains isolated from vaginas of asymptomatic pregnant women in Beijing were obtained.Ribotyping was carried out using the fragment of 16SrRNA as probe. The presence of bac, bca, ScpB, GlnA , and ScaA genes was detected in the genome of GBS strains by hybridization. Results All Strains contained genes of ScpB, ScaA, GlnA ; Strains belonging to serotype Ⅱ、Ⅱ/C have bca and bac genes; Most(60%) of strains belonging to Ia bac dorit have and bca genes.Strains expressing the serotype Ⅲ、Ⅲ/R lack of bca and bac genes. Only 3 different HindⅢ patterns, 7 and 10 different EcoRI and PvuII patterns among 34 strains, respectively; with the combination of three restriction endonucleases, a total 16 distinct ribotypes were obtained among 34 isolates; Combined analysis of all of our data revealed 22 distinct clonal genotypes. Conclusion Ribotyping genetic typing system should be useful for molecular epidemiological study of GBS; The combination of more molecular typing methods has potential value in the epidemiological study.