一种简单准确的微生物活菌计数方法

A Simple and Accurate Method for Enumeration of Viable Bacteria

目的:探讨微量点样法用于计数微生物活菌数的可行性。方法:分析了菌种、培养基和点样量对测定结果的影响,并与平板涂布法计数结果进行了比较和相关性及线性回归分析。结果:微量点样法的菌落生长特点受菌种、培养基和点样量的影响较小;活菌计数结果与平板涂布法相比,(1)对8种测试菌株(约108CFU/mL)均没有显著性差异(P>0.05);(2)对4种不同类型细菌(Escherichia coli,Pseudomonas aeruginosa,Streptococcus pneumoniae and Bacteroides fragilis,约107～109CFU/mL)均具有极显著的直线回归关系(P<0.01,n=5),其回归方程分别为y=1.0740x-0.4144(R2=0.9881),y=0.8100x+1.4789(R2=0.9977),y=1.1194x-0.7373(R2=0.9806),y=0.9107x+0.772(R2=0.9812)。结论:微量点样法简化了平板涂布法的操作过程,适应性广、准确性高,因此,是一种简单、经济的细菌活菌计数方法。

Objective： A simple drop plate method for enumeration of viable microorganisms was developed and tested. Method： The effects on bacteria, culture media and drop sizes were discussed. And viable bacterial counts between the drop plate method and the spread plate method were compared and conducted by corresponding analysis and linear regression. Result： the colonial morphology inoculated by the drop plate method was less under the influence of bacterial species, culture media and the size of the drop; the viable counts obtained by the drop plate method compared with the spread plate method, （ 1 ） for 8 bacteria （ about 10SCFU/mL） , there were no signification differ- ence （ P 〉 0. 05 ） ; （2） for 4 kinds of strains （ Escherichia coli, Pseudomonas aeruginosa, Streptococcus pneumoniae and Bacteroides fragi- l/s, about 107 - 109 CFU/mL）, there was a good liner relationship （ P 〈 O. 01, n = 5 ）, the regression equations were y = 1. 0740x -0.4144 （R^2 =0,9881）, y =0.8100x ＋ 1.4789 （R^2 =0.9977）, y = 1.1194x-0.7373 （R^2 =0.9806）, y =0.9107x ＋0.772 （R^2 = 0. 9812）, respectively. Conclusion：The drop plate method is easy to operate, wide adaptability and high accuracy. Thus, it is a simply and economical method for enumeration of viable bacteria,