不同环境因素对表皮葡萄球菌生物膜形成的影响

采用微量板半定量法研究影响表皮葡萄球菌生物膜形成的因素,同时模拟奶牛体内环境因素,如乳糖、酪蛋白和Ca2+等,探索不同理化因素对表皮葡萄球菌生物膜形成的影响,结果表明,检测的3种培养基中,胰蛋白胨大豆肉汤(Typtic Soy Broth,TSB)培养基最有利于表皮葡萄球菌的生长及其生物膜的形成,且最适质量分数为3%左右;在pH中性条件下,NaCl对表皮葡萄球菌生物膜的形成有明显抑制作用;当pH大于7时,表皮葡萄球菌生物膜形成能力明显减弱。在模拟奶牛体内环境因素中,一定质量分数的Ca2+(0.2%及以上)与高质量分数的乳糖(8%及以上)对生物膜形成有明显抑制作用,而外源添加酪蛋白对表皮葡萄球菌生物膜形成没有明显影响。

Effects of Different Factors on Biofilm Formation by Staphylococcus epidermidis

Semi-quantitative assay was performed to examine the effects of factors in vitro and in vivo on biofilm formation by Staphylococcus epidermidis.The explored factors included medium,glucose and sucrose,pH value,sodium chloride,lactose,casein and Ca2+.The results showed that typtic soy broth(TSB)was the most preferable medium for both growth and biofilm formation of S.epidermidis in three tested media,and the optimum concentration of TSB was about 3%.Different concentrations of sodium chloride showed an obvious inhibition against S.epidermidis’s biofilm formation at pH 7.When the pH value of medium was more than 7,the ability of biofilm formation by S.epidermidis was significantly reduced while the cell growth was normal.In simulative in vivo factors,a certain concentration of Ca2+(no less than 0.2%) and high concentration of lactose(no less than 8%) obviously inhibited biofilm formation by S.epidermidis,while the addition of casein to medium had no obvious effect on biofilm formation of S.epidermidis.