大肠埃希菌细菌计数分光光度计法的建立及应用

Establishment and Application of Escherichia coli Counting Method Based on Spectrophotometer

利用分光光度计实现大肠埃希菌快速细菌计数方法的建立及应用。分别在450、570、600、650nm 4个波长下,用分光光度计对大肠埃希菌菌悬液进行平板计数与吸光度值测量,确定大肠埃希菌细菌数量与吸光度值之间的线性关系及测量菌液浓度的最佳波长。经测定,上述波长在一定吸光度值范围内,大肠埃希菌细菌数量与吸光度值之间线性关系良好,其中线性关系成立最好的波长为600nm。在600nm波长下,建立以测定所得吸光度值(OD值)为横坐标,平板计数所得细菌数(×10^6 CFU/mL)为纵坐标描述二者相关线性关系的标准曲线,曲线回归方程为y=1 437.3x-27.344(R^2=0.998)。经应用验证,该回归方程可信度达95%。利用所得曲线为细菌计数提供一种可供选择的方法,可以实现药敏试验等相关微生物试验中大肠埃希菌的快速计数。

To establish a rapid counting method for Escherichia coli by a spectrophotometer,at the wavelength of 450nm,570nm,600nm,and 650nm,the linear relationship between the number of Escherichia coli bacteria and the absorbance value was determined by plate counting and OD value determination of different concentrations of Escherichia coli bacterium solutions.After the measurement,the linear relationship between the number of Escherichia coli bacteria and absorbance values was good at four wavelengths of 450nm,570nm,600nm,and 650nm,and the best linear relationship was at 600nm.At the wavelength of 600nm,a standard curve describing the linear relationship between OD values and bacterial counts(×106 CFU/mL)were established in abscissa and longitudinal coordinates.The curve regression equation was y=1437.3x-27.344(R2=0.998).It verified that the regression equation has a credibility of 95%.The curve provided an alternative method for Escherichia coli bacterial counting,which could be used for the rapid count of Escherichia coli in drug sensitivity test and other related microbial tests.