金黄色葡萄球菌(Staphylococcus aureus)液体增菌培养基的优化

Research on optimization of the enrichment broth of Staphylococcus aureus

为研发一种金黄色葡萄球菌(Staphylococcus aureus)选择性增菌液,选用针对革兰氏阴性菌及非葡萄球菌属菌株具有选择抑制作用的7.5%氯化钠肉汤作为基础培养基,探索氨基酸、丙酮酸钠、甘露醇对金黄色葡萄球菌的促生长能力,通过正交试验确定培养基的最优配方,并使用优化后的培养基与原始培养基作用于来源不同的四株金黄色葡萄球菌标准菌株,对其增菌效果和抑制大肠杆菌(Escherichia coli)的效果进行对比。结果表明,最佳培养基配方为在基础培养基上添加L-丙氨酸1.0 g/L、甘露醇6.0 g/L、丙酮酸钠1.2 g/L。菌株在优化后培养基上增菌浊度及转接至Baird-Parker的菌落数上均有促进效果,最终菌株的OD550 nm值有0.28~0.34的增长,转接Baird-Parker后的菌落数也有10~100倍的增长,且在促进目标菌生长的同时对大肠杆菌的抑制性也没有受到影响,表明该增菌培养基选择性良好。

In order to develop a selective growth solution for Staphylococcus aureus,using 7.5%sodium chloride broth as an initial broth with selective inhibition against Gram-negative bacteria and non-Staphylococcal strains as the base medium,the growth promotion ability of amino acids,sodium pyruvate and mannitol on S.aureus was investigated,and the optimal medium formula was determined by orthogonal tests.Four standard strains of S.aureus from different sources were treated with the optimized medium and the original base medium,and the effect of increasing bacteria and inhibiting Escherichia coli were compared.The results showed that the optimal medium was supplemented with L-alanine 1.0 g/L,mannitol 6.0 g/L and sodium pyruvate 1.2 g/L on the basis of base medium.After the optimization,the turbidity of the strains increased and the number of colonies transferred to Baird-Parker were improved.The OD550 nm value of the strain increased by 0.28-0.34,and the number of colonies after the transfer to Baird-Parker also increased by 10-100 times.While promoting the growth of target bacteria,the inhibition of E.coli was not affected,which indicated that the culture medium had good selectivity.