硒化甘草多糖联合抗生素对奇异变形杆菌体内外抑菌效果以及抑菌机制研究

Study on in vitro and in vivo antibacterial effect and antibacterial mechanism of selenide Glycyrrhiza polysaccharide combined with antibiotics against Proteus mirabilis

试验旨在探究硒化甘草多糖(SeGUP)和甘草多糖(GUP)联合抗生素对奇异变形杆菌(PM)的体内外抑菌效果以及抑菌机制。体内外抑菌效果通过药敏试验、最小抑菌浓度(MIC)、生长曲线、体外协同作用以及SeGUP、GUP对PM感染小鼠的死亡率进行分析。抑菌机制通过PM细胞壁、细胞膜、生物膜、抗氧化酶活性的变化进行分析。结果显示,同浓度SeGUP比GUP抑菌圈大,MIC值小,对PM生长抑制更强;SeGUP与环丙沙星(CI)联合表现为协同,GUP与CI表现为相加;SeGUP能够极显著降低PM感染小鼠死亡率(P<0.01)。与对照组相比,SeGUP、GUP、CI可极显著升高培养液中碱性磷酸酶(AKP)、β-半乳糖苷酶(β-gal)的活性和蛋白含量(P<0.01),极显著降低菌体DNA含量,抑制生物膜形成,降低过氧化氢酶(CAT)、超氧化物歧化酶(SOD)活性(P<0.01)。结果表明,SeGUP体内外抑菌效果以及抑菌机制能力均优于GUP。

The study was to investigate in vitro and in vivo antibacterial effect andantibacterial mechanism of selenide Glycyrrhiza polysaccharide(SeGUP)and Glycyrrhiza polysaccharide(GUP)combined with antibiotics against Proteus mirabilis(PM).In vitro and in vivo bacteriostatic effect of SeGUP and GUP were analyzed by drug susceptibility test,minimum inhibitory concentration(MIC),growth curve,in vitro synergy,and effect of SeGUP and GUP on mortality of PM-infected mice.Bacteriostasis mechanism was analyzed by studying changes of PM cell wall,cell membrane,biofilm and antioxidant enzyme activities.The results showed that compared with GUP,SeGUP at same concentration had a larger inhibitory circle and a smaller MIC,which inhibited the growth of PM more strongly.SeGUP combined with CI showed a synergistic effect,while GUP combined with CI showed a additive effect.SeGUP extremely reduced mortality of PM-infected mice(P<0.01).Compared with control group,SeGUP,GUP,CI could extremely increase the activity of alkaline phosphatase(AKP),β-galactosidase(β-gal)and protein content in culture medium(P<0.01),extremely reduced intracellular DNA concentration,inhibited biofilm formation,reduced activity of catalase(CAT)and superoxide dismutase(SOD)(P<0.01).The study indicates that in vitro and in vivo antibacterial effect of SeGUP and its antibacterial mechanism are better than that of GUP.