粪肠球菌类毒力基因sprE功能的动物实验研究

Experimental research on the role of the putative virulence factor sprE of Enterococcus faecalis in mouse and rabbit models

目的 构建粪肠球菌丝氨酸蛋白酶基因（sprE）突变株，通过动物实验来研究sprE基因的功能。方法 通过小鼠腹膜炎模型和兔心内膜炎模型来评价粪肠球菌sprE基因的突变株（sprEmutant）的毒力下降情况。结果突变株在小鼠腹膜炎模型中的半数致死量（LD50）提高了7倍，小鼠的存活率明显高于野生株感染组，引起的兔心内膜炎的病理改变也较野生株轻微。结论 sprE基因在粪肠球菌致病中起着重要的作用，可能是粪肠球菌的毒力因子之一。

Objective To construct the serine protease gene （sprE） mutant and to explore the role of sprE gene of Enterococus faecalis by a mouse and rabbit models. Methods The isogenic sprE deficient mutant was created by allelic recombinant. Moreover, virulence decrease of sprE mutant was examined by a mouse peritonitis and a rabbit endocarditis models. Results Approximately seven fold higher 50% lethal dose（LD50 ） of sprE mutant was found, the percentage of survival in models was higher than wild-type OG1RF. The pathological change is lighter than wild-type OG1RF in a rabbit endocarditis model. Conclusion sprE is important in the pathogenesis of Enterococcus faecalis, as a potentially main virulence factor of Enterococcus faecalis.