基于固体培养基的金黄色葡萄球菌计数方法的相关性研究

目的 基于固体培养条件下对金黄色葡萄球菌传统计数方法 的比较研究,并探讨A600值和金黄色葡萄球菌活菌数二者之间的关系.方法金黄色葡萄球菌在固体条件下培养至对数生长期,无菌生理盐水制成菌悬液,采用平板计数法、麦氏比浊法、显微计数法检测菌悬液,同时记录3种方法计数结果 ;在相同培养条件下初步稀释后检测菌液的吸光度(A600)值,取A600值在0.2～1间的菌液进一步稀释并检测A600,同时对各个稀释度的菌液进行平板菌落计数.结果在固体培养条件下,传统细菌计数方法计数结果:显微计数法>平板计数法>比浊法;同时A600值和金黄色葡萄球菌活菌数二者之间呈线性相关,线性回归方程为Y=28.98601X-0.17331,A600值(X),菌液浓度(Y×107cfu/mL).结论 基于固体培养条件下,3种传统计数方法之间存在各自的特点.同时,金葡菌菌液的吸光度与金黄色葡萄球菌活菌数之间呈良好的相关性,适用于金黄色葡萄球菌浓度的测定.

Comparison of different counting methods of Staphylococcus aureus based on solid medium

Objective To compare the different counting methods of Staphylococcus ( S.) aureus based on solid medium, and study the relationship between the A600 value and the plate counting method. Methods S. aureus was incubated to logarithmic growth phase on solid medium, and then washed by sterile saline. Bacterial suspension was tested by the plate counting method, McFarland′s turbidimetry and microscopic counting method. The A600 value of the bacterial suspension was measured after the initial dilution. When the A600 value between 0.2-1 was taken to further dilution and detection, and each dilution was calculated by the plate counting method. Results Comparison of traditional bacterial counting methods, the microscopic counting method was superior to the plate counting method and McFarland' s turbidimetry. There was a linear correlation between the A600 value and the plate counting method, linear regression equation was Y=28.98601X-0.17331. Conclusion Three traditional counting methods have their own characteristics based on the solid culture conditions. There is a good correlation between the absorbance of S. aureus and the viable count of S. aureus, which is suitable for determination of S. aureus concentration.