外排泵msrA在表皮葡萄球菌生物被膜对红霉素耐药性中的作用

Role of efflux pump msrA in erythromycin resistance of Staphylococcus epidermidis biofilm

目的:探讨外排泵msrA在表皮葡萄球菌生物被膜对红霉素耐药性中的作用.方法:从野生菌株中克隆msrA基因全长,并通过穿梭载体pBT2电转化至限制缺陷菌株金黄色葡萄球菌RN4220,提取质粒后再转化S.epidermidis 1457(ica+,产膜阳性菌),得到S.epidermidis 1457-msrA.实时荧光RT-PCR检测S.epidermidis 1457-msrA和野生株S68浮游菌、生物被膜内细菌红霉素作用24h前后msrA mRNA的表达.结果:表葡膜内菌msrA的表达在红霉素(10倍MIC)作用前后未见统计学差异.结论:提示膜内菌对红霉素耐药性的增加可能与外排泵基因的上调无关.

AIM： To confirm whether the upregulation of the efflux pump msrA is related to erythromyein resistance in Staphy- lococcus epidermidis （ S. epidermidis ） biofilm. METHODS ： The full length of msrA was cloned and inserted into shuttle vector pBT2. The recombinant plasmid was eleetroporated into restrie- tion-defieient S. aureus RN4220. The plasmid isolated from S. aureus RN4220 was eleetroporated into S. epidermidis 1457. The expression of msrA mRNA in planktonie and biofilm eells of S. epidermidis 1457-msrA and wild isolate S68 were evaluated by real-time quantitative RToPCR. RESULTS： The expression of msrA in S. epidermidis 1457-msrA mRNA and wild isolate $68 biofilms showed no signifieant differenee before and after erythro- myein treatment. CONCLUSION： The erythromyein resistanee in S. epidermidis biofilm is not related to the upregulation of the msrA.