嗜酸乳杆菌S-层蛋白联合抗生素对Escherichia coli和Staphylococcus aureus的抑制作用研究

Antibacterial Action of Lactobacillus acidophilus S-layer proteins Combined with Antibiotics on Escherichia coli and Staphylococcus aureus

旨在检测嗜酸乳杆菌S-层蛋白以及S-层蛋白与抗生素联用对大肠杆菌(Escherichia coli)和金黄色葡萄球菌(Staphylococcus aureus)的抑制作用。采用液体发酵培养法获得嗜酸乳杆菌菌体,LiCl法提取S-层蛋白粗提物,凝胶过滤层析法纯化S-层蛋白,分别用E.coli和S.aureus处理Caco-2细胞2 h后,考察S-层蛋白在不同浓度和不同作用时间条件下对E.coli和S.aureus的抑制作用,并考察S-层蛋白联合抗生素对E.coli和S.aureus的抑制作用,实验分组:(1)空白对照;(2)嗜酸乳杆菌组;(3)S-层蛋白组;(4)抗生素组;(5)嗜酸乳杆菌+抗生素组;(6)S-层蛋白+抗生素组。结果显示,液体发酵得到嗜酸乳杆菌菌体,提取并纯化得到S-层蛋白;S-层蛋白对E.coli和S.aureus有很好的抑制效果,具有浓度依赖性,高浓度下抑制率达到42.2%和31.7%,差异极显著(P<0.01),且在E.coli和S.aureus作用的短时间内干预效果明显,0 h时的抑制率分别达到59.3%和48.4%;S-层蛋白联合抗生素的抑菌率分别达到81.7%和79.3%,差异极显著(P<0.01),效果优于单独使用抗生素。嗜酸乳杆菌S-层蛋白具有较强的抑菌作用,可以与抗生素联用,有望开发称为一种新型的抗菌药物。

This work aims to detect the antibacterial action of S-layer proteins of Lactobacillus acidophilus and the combination of the S-layer proteins with antibiotics on Escherichia coli or Staphylococcus aureus.L.acidophilus was cultivated via liquid fermentation,S-layer proteins crude extract were obtained with LiCl extraction,and the S-layer proteins was purified with gel filtration chromatography.At 2 h after infecting the Caco-2 with E.coli and S.aureus respectively,the inhibition effects of S-layer proteins on E.coli and S.aureus under different concentration and different impact times were investigated,also the inhibition effect of S-layer protein combined with antibiotics on E.coli and S.aureus was studied.The experiments were grouped as:(1)control,(2)L.acidophilus,(3)S-layer proteins,(4)antibiotics,(5)L.acidophilus+antibiotics,and(6)S-layer proteins+antibiotics.Results showed that L.acidophilus was harvested by liquid fermentation,S-layer proteins were extracted and purified.S-layer proteins demonstrated the fine inhibition to E.coli and S.aureus in a dosage-dependent way,the inhibition rate reached 42.2%and 31.7%respectively under high concentration,and the difference was extremely significant(P<0.01).The interference effect was obvious in short time after E.coli and S.aureus intervened,and the inhibition rate reached 59.3%and 48.4%respectively at 0 h.The inhibition rate of S-layer proteins combined with antibiotics reached 81.7%and 78.3%respectively,the difference was extremely significant(P<0.01),and the effect was better than antibiotics alone.In conclusion,L.acidophilus S-layer proteins present strongly antibacterial effect,it can be co-used with antibiotics,and it is expected to be develop as a new type of antibacterial drug.