表皮葡萄球菌ΔvraSR-lrgAB突变株的构建和生物学特性

Construction and characterization of ∆vraSR-lrgAB of Staphylococcus epidermidis

摘要:

目的 探究VraSR通过CidA-LrgAB系统调控表皮葡萄球菌的生物学功能。方法 构建重组质粒pKOR1-ΔlrgAB，并将其转化至表皮葡萄球菌SE1457 ?vraSR突变株中。通过同源重组技术，在?vraSR突变株上进一步敲除lrgAB基因。利用PCR、RT-PCR和测序技术鉴定表皮葡萄球菌ΔvraSR-lrgAB疑似突变株，并检测其生长特性、药物敏感性、自溶能力以及生物被膜形成能力。结果 成功构建了表皮葡萄球菌?vraSR-lrgAB突变株。与表皮葡萄球菌SE1457、ΔvraSR和ΔlrgAB菌株相比，?vraSR-lrgAB突变株生长迟缓，特别是在25 ℃和40 ℃下尤为明显(P<0.001)。该突变株的药物敏感性增强(P<0.01)，自溶能力显著增强(P<0.001)，生物被膜形成能力降低(P<0.01)。结论 VraSR可能部分通过LrgAB调控表皮葡萄球菌的生长、药物敏感性、自溶能力和生物被膜的形成。

Abstract:

Objective To explore the role of VraSR in regulating the biological functions of Staphylococcus epidermidis via the CidA-LrgAB system.Methods The recombinant plasmid pKOR1-ΔlrgAB was constructed and then electroporated into SE1457 ?vraSR to delete lrgAB from the genome of ?vraSR by homologous recombination. The suspected mutant ?vraSR-lrgAB was verified by PCR, RT-PCR, and sequencing. The growth, drug susceptibility, autolysis, and biofilm formation of ?vraSR-lrgAB were determined.Results The S. epidermidis mutant ?vraSR-lrgAB was successfully constructed. Compared with SE1457, ?vraSR, and ?lrgAB, ?vraSR-lrgAB exhibited retarded growth, especially at 25 ℃ and 40 ℃ (P<0.001), increased drug susceptibility (P<0.01), enhanced autolysis (P<0.001), and reduced biofilm formation (P<0.01).Conclusion VraSR may regulate the growth, drug susceptibility, autolysis, and biofilm formation of S. epidermidis partly via the LrgAB system.