耐甲氧西林表皮葡萄球菌 psm-mec 缺失突变株的构建  

Construction of mutant strains of methicillin resistant Staphylococcus epidermidis with psm-mec gene deletion

作　　者：杨永长[1] 胡洪华[1] 陈亮[1] 刘华[1] 喻华[1] 黄文芳[1] 

机构地区：[1]四川省医学科学院,四川省人民医院检验科,成都610072

出　　处：《中华微生物学和免疫学杂志》2015年第9期672-677,共6页Chinese Journal of Microbiology and Immunology

摘　　要：目的：构建耐甲氧西林表皮葡萄球菌（ MRSE）的psm-mec缺失突变株，并对psm-mec的功能进行初步研究。方法运用药敏试验、DNA序列分析技术筛选psm-mec上下游序列与S．epi-dermidis标准菌株RP62A完全一致且四环素和氯霉素敏感的MRSE。利用融合PCR和温度敏感性穿梭质粒构建同源重组质粒pBT2-Δpsm-mec，经鉴定后电转金黄色葡萄球菌RN4220进行修饰，提取质粒后电转用于构建缺失突变的临床分离MRSE，经同源重组后筛选和鉴定psm-mec缺失突变株。分析缺失突变株与野生株生物被膜形成能力的差异，验证psm-mec与MRSE生物被膜的关系。结果通过序列比对和药敏试验筛选和鉴定了3株用于构建psm-mec缺失突变的临床分离MRSE。通过同源重组，筛选和鉴定获得psm-mec缺失突变株。与相应的野生株比较，3株缺失突变株生物被膜形成能力明显降低，提示psm-mec可诱导MRSE生物被膜形成。结论成功获得耐甲氧西林表皮葡萄球菌psm-mec缺失突变株，psm-mec与表皮葡萄球菌生物被膜形成相关。Objective To construct mutant strains of methicillin resistant Staphylococcus epidermi-dis （MRSE） with psm-mec gene deletion and to investigate the function of psm-mec gene.Methods The drug sensitivity test and DNA sequence analysis were performed to screen out the tetracycline and chloram -phenicol sensitive clinical strains of MRSE , whose upstream and downstream sequences of psm-mec gene were identical to those of the Staphylococcus epidermidis reference strain RP62A.The recombinant plasmid pBT2-Δpsm-mec was constructed by using the fusion PCR and a temperature sensitive shuttle plasmid .After being identified , the plasmid was transformed into the Staphylococcus aureus RN4220 strain by electropora-tion, and then transformed into the selected clinical isolates of MRSE .The mutant strains of MRSE with psm-mec deletion were screened out and identified after homologous recombination .The differences in biofilm formation between the mutant and wild-type strains were analyzed for further elucidation the relationships be-tween the psm-mec gene and biofilm formation in MRSE strains .Results Three clinical MRSE isolates for the construction of mutant strains with psm-mec gene deletion were screened out and identified by using drug sensitivity test and sequence alignment analysis .The mutants constructed via homogenous recombination were screened out and identified .Compared with the corresponding wild-type strains, the three mutants with psm-mec gene deletion showed significantly decreased ability of biofilm formation , demonstrating that the psm-mec genes strains induced the biofilm formation of MRSE .Conclusion The Δpsm-mec mutant strains were successfully constructed .The psm-mec gene played an important role in the biofilm formation of Staphy-lococcus epidermdis.

关 键 词：表皮葡萄球菌 同源重组 突变体 生物被膜形成 

分 类 号：R378.11[医药卫生—病原生物学]