插入序列IS861和IS1548与B族链球菌的表型及分型关系的研究  

The Relation of Insertion Elements IS861 and IS1548 to Genotype and Phenotype of Group B Streptococci

作　　者：杨明[1] 杨永弘[2] Dmitriev Alexander 申阿东[2] 佟月娟[2] 樊寻梅[1] 

机构地区：[1]首都医科大学附属北京儿童医院急救中心 [2]首都医科大学附属北京儿童医院儿科研究所 [3]俄罗斯圣彼得堡实验医学研究院

出　　处：《首都医科大学学报》2007年第4期471-475,共5页Journal of Capital Medical University

基　　金：国家科技部中俄政府间合作项目~~

摘　　要：目的 观察基因组插入序列IS861、IS1548在B族链球菌(GBS)基因组中的出现规律,探讨其与细菌表型如毒力、耐药性、血清分型的关系,评价插入序列用于细菌分子生物学分型的价值.方法 采用PCR-RFLP(限制性片段长度多态性分析)、核酸探针和Southern杂交等技术对采自北京、广州和圣彼得堡的113株GBS菌进行基因组插入序列研究.结果 在113株GBS中,有67株(59.3%)和13株(11.5%)分别含IS861和IS1548,不同城市GBS菌株的插入序列阳性率无统计学差异;含IS1548的13株GBS都同时含IS861,全部属于血清Ⅲ型,且此类菌株含相对较多的插入序列拷贝.含插入序列的GBS菌株普遍具有较高的红霉素耐药性.67株菌IS861阳性菌株共产生9种HindⅢ的RFLP分型,不同分型的拷贝数为1-9个.13株IS1548阳性GBS中,共产生6种EcoRⅠ的RFLP杂交类型,拷贝数为8～9个.结论 插入序列在GBS基因组中插入的现象比较普遍,血清Ⅲ型GBS的特殊生物特性与IS861和IS1548插入密切相关,大部分血清Ⅲ型GBS可能来自同一个毒力克隆,对携带此型菌株的产妇或新生儿应引起临床重视;IS861和IS1548可能通过影响耐药基因的表达调控GBS对红霉素的敏感性;血清分型与插入序列的RFLP分型相结合能显著提高GBS菌株的分型率,可作为一种重要的方法用于GBS的流行病学研究.Objective To observe the presence pattern of two insertion elements,IS 861 and IS 1548 in the genome of Group B streptococci(GBS);to study the relationship between the insertion elements in the genome and the phenotypes of GBS(virulence,drug resistance,and serotype);and to access the value of insertion elements in genotyping.Methods IS861 and IS1548 were studied with PCR-restriction fragment length polymorphism(RPLP),nucleic acid probe and Southern blot in 113 strains isolated in Beijing,Guangzhou and St.Petersburg.Results Of the 113 GBS strains,67(59.3%) and 13(11.5%) possessed IS861 and IS1548 respectively.There was no significant difference in positive insertion rate of the two elements among the strains isolated in the three cities.Thirteen strains with IS1548 additionally possessed IS861 and all belonged to serotype Ⅲ.Relatively larger number of insertion element copies were discovered in the genome of these strains.The GBS strains possessing insertion element(s) showed a significantly higher erythromycin resistance rate.Nine HindⅢ restriction patterns,hybridized with gene probe IS861 were found in 67 insertion element positive strains,and the copy numbers varied from 1～9;while 6 EcoRⅠrestriction patterns,hybridized with IS 1548 gene probe,were found in 13 strains with the copy number varied form 8～9.Conclusion The insertion of insertion element(s) is common in the genome of GBS.IS861 and IS1548 are closely related to the special properties of GBS serotype Ⅲ.Most of the strains of serotype Ⅲ were believed to be from a same pathogenic clone,and clinical attention should be paid to the women and neonates carrying GBS serotype III.IS861 and IS1548 may modulate the erythromycin susceptibility of GBS by affecting the expression of erythromycin resistant genes.The comparative study of different typing method suggest that the combination of genotyping by insertion elements PCR-RFLP and serotyping demonstrate a good discriminative value in epidemiological study of GBS.

关 键 词：链球菌 无乳 DNA转座因子 基因分型 血清分型 耐药性 

分 类 号：Q75[生物学—分子生物学]