包装饮用水中铜绿假单胞菌两种定量检验方法比较

Comparison of 2 kinds of quantitative detection methods for Pseudomonas aeruginosa in packaged drinking water

目的结合国家标准中铜绿假单胞菌的检测方法,探究适合铜绿假单胞菌定量的检测方法。方法设计两种定量检测方法对国家标准方法进行优化:稀释过滤法,先将样液进行稀释,对每个稀释度的样液抽滤250 mL;线性过滤法,分别抽滤1、5、10、20、30、40、50 mL样液,计算抽滤液中的菌数,建立回归方程,并由回归方程计算得到每250 mL样液中铜绿假单胞菌的数量。采用3个浓度梯度的样液:样液A浓度为22 CFU/100 mL、样液B浓度为120 CFU/100 mL、样液C浓度为213 CFU/100 mL,分别用两种方法进行检测,并与样液的真实浓度为对比,得出较佳的检测方法。结果稀释过滤法对3种浓度的样液检测结果都与真实值无显著差异;线性过滤法在检测样液A时结果与真实值有明显差异(P<0.01),在检测样液B、C时,结果与真实值无显著差异。结论稀释过滤法和线性过滤都能较好地反映出待测样液中铜绿假单胞菌的浓度。

Objective To explore the suitable quantitative detection methods of Pseudomonas aeruginosa,combined with the detection methods of Pseudomonas aeruginosa in national standards.Methods Two kinds of quantitative detection methods were designed to optimize the national standard method:Dilution filtration method:First,the sample solution was diluted,and 250 mL of sample solution with each dilution degree was filtered by suction;linear filtration method was used to filter 1,5,10,20,30,40 and 50 mL of sample solution,to calculate the number of bacteria in the filtrate and establish a regression equation,and the number of Pseudomonas aeruginosa in every 250 mL of sample solution was calculated from the regression equation.The sample solutions with 3 concentration gradients:Sample solution A concentration of 22 CFU/100 mL,sample solution B concentration of 120 CFU/100 mL,and sample solution C concentration of 213 CFU/100 mL were tested by 2 kinds of methods,respectively,and compared with the actual concentration of sample solution,the better test method was obtained.Results The results of dilution filtration method for the sample solutions at the 3 kinds of concentrations were not significantly different from the true values,the result of linear filtration method was significantly different from the true value in the detection of sample solution A(P<0.01),while the results were not significantly different from the true values in the detection of sample solutions B and C.Conclusion The dilution filtration method and linear filtration method can reflect the true concentration of Pseudomonas aeruginosa in the sample solution to be tested.