Huang H, Oberkötter E, Blume H
Zentrallaboratorium Deutscher Apotheker, Eschborn.
Pharmazie. 1994 Jun;49(6):428-32.
A test method for the determination of Escherichia coli in plant materials with the MUG (Fluorocult)-lauryl sulfate broth is described. It was found that more than 75% of the commonly used vegetable drugs exhibit fluorescence quench effects to different degrees when determining E. coli with the MUG-lauryl sulfate broth. Therefore a simple combination of two procedures was evaluated in order to avoid the matrix interferences: in a first step the drug sample was diluted eight times in a proportion of 1:10 with MUG-lauryl sulfate broth in eight separate tubes from 1 g down to 10(-7) g/tube (1st test series) and the resulting samples were incubated for 40 h at 36 degrees C. Subsequently, the tubes were tested for fluorescence. If the first tube of this series was found without fluorescence, in a second step a subsequent series of MUG-lauryl sulfate broth (2nd test series) was inoculated with 0.5 ml of the incubated culture from each of the first three tubes of series 1 and incubated again for 24 h at 36 degrees C. The results were evaluated from gas production, fluorescence as well as indole formation. Thus, the method allowed a simple and reproducible enumeration of E. coli for the test on microbial contamination in medicinal plant materials. The method was successfully applied to samples of 38 vegetable drugs for quantitative determination of E. coli (8 samples were found being contaminated with E. coli).
描述了一种用MUG（荧光培养）-月桂基硫酸盐肉汤测定植物材料中大肠杆菌的测试方法。研究发现，在用MUG-月桂基硫酸盐肉汤测定大肠杆菌时，超过75%的常用植物药表现出不同程度的荧光猝灭效应。因此，为避免基质干扰，对两种方法的简单组合进行了评估：第一步，将药物样品在8个单独的试管中用MUG-月桂基硫酸盐肉汤按1:10的比例稀释8倍，从1 g到10(-7) g/管（第1个测试系列），所得样品在36℃下孵育40 h。随后，对试管进行荧光测试。如果该系列的第一管未发现荧光，则在第二步中，用系列1前三管中每管0.5 ml的孵育培养物接种后续的MUG-月桂基硫酸盐肉汤系列（第2个测试系列），并在36℃下再次孵育24 h。根据产气、荧光以及吲哚形成情况对结果进行评估。因此，该方法能够对药用植物材料中的微生物污染测试进行简单且可重复的大肠杆菌计数。该方法已成功应用于38种植物药样品的大肠杆菌定量测定（发现8个样品被大肠杆菌污染）。
