甘露醇氯化钠琼脂培养基成分对鉴定金黄色葡萄球菌的影响

Effects of composition of mannitol salt agar on identification of Staphylococcus aureus

目的 探究甘露醇氯化钠琼脂培养基成分中氯化钠和胰酪胨对甘露醇氯化钠琼脂培养基质量的影响,同时考察市售5个国产品牌和1个进口品牌的甘露醇氯化钠琼脂培养基的产品质量。方法 采用不同品牌不同浓度的氯化钠和胰酪胨配制成甘露醇氯化钠琼脂培养基,应用平板涂布计数、半定量划线法探究氯化钠和胰酪胨对甘露醇氯化钠琼脂培养基质量的影响;对不同种金黄色葡萄球菌和大肠杆菌在5个国产品牌和1个进口品牌的甘露醇氯化钠琼脂培养基上的生长情况进行定量测定。参照GB 4789.28-2013比较不同品牌培养基对不同菌株的生长率、生长指数和菌落大小的影响,对培养基质量进行评价。结果 实验菌株在使用不同种类、不同浓度的氯化钠或胰酪胨配制的甘露醇氯化钠琼脂培养基上的生长率、生长指数存在较大差异;不同品牌的甘露醇氯化钠琼脂培养基非目标菌生长指数均合格,但目标菌的生长率和菌落生长大小存在显著差异。结论 氯化钠和胰酪胨对于甘露醇氯化钠琼脂培养基质量影响较大,会直接决定培养基的质量是否合格,市售的国内外不同品牌甘露醇氯化钠琼脂培养基质量存在较大差异,国产甘露醇氯化钠琼脂培养基的质量优于进口培养基。

Objective To explore the effects of sodium chloride and tryptone in the components of mannitol salt agar on the quality of mannitol salt agar,and investigate the product quality of 5 domestic brands and 1 imported brand of mannitol salt agar sold on the market.Methods The effects of sodium chloride and tryptone with different brands and concentrations of sodium chloride and tryptone on the quality of mannitol salt agar were investigated using plate coating counting and semi quantitative scoring method.Quantitative determination of the growth of different types of Staphylococcus aureus and Escherichia coli on 5 domestic brands and 1 imported brand of mannitol salt agar.Referring to GB 4789.28—2013,the growth rate,growth index,and colony size of different brands of culture media for different strains were compared,and the quality of each brand of culture media was evaluated.Results There were significant differences in the growth rate and growth index of experimental strains on mannitol salt agar prepared with different types and concentrations of sodium chloride or tryptone.The growth index of non target bacteria in different brands of mannitol salt agar was qualified,but there were significant differences in the growth rate and colony size of the target bacteria.Conclusion Sodium chloride and tryptone have a significant impact on the quality of mannitol salt agar,which directly determines whether the medium is qualified.There are significant differences in the quality of different brands of mannitol salt agar sold domestically and internationally,and the quality of domestic mannitol salt agar is better than that of imported medium.