Davis W W, Stout T R
Appl Microbiol. 1971 Oct;22(4):659-65. doi: 10.1128/am.22.4.659-665.1971.
Several factors are investigated that normally cause variation in zone diameters in conventional disc plate diffusion assay procedures. Of these factors the most serious is the unequal exposure of the individual plates at top or bottom of stacks to temperatures above and below room temperature. This unequal temperature exposure is avoided by novel handling and incubation procedures. A major variable, but one which can be controlled, is the varying time interval between pouring seeded agar and the time of applying the pads with antibiotic to the plates. This influence of time of setting and the effects of several other sequential operations are combined into a composite variable. This variable is then accounted for and normalized by interposing "external" reference plates set with a reference solution in the sequence of approximately 100 plates. No "internal" reference zones are employed. Such factors as volume of agar poured, wedge shape of agar in a dish, volumetric errors in dilutions, and timing considerations are studied and discussed. The results of this study form the basis for a test protocol which is presented in a following paper.
研究了常规纸片扩散试验程序中通常导致抑菌圈直径变化的几个因素。在这些因素中，最严重的是叠放的平板顶部或底部的单个平板暴露于高于和低于室温的温度下的程度不均。通过新颖的处理和培养程序避免了这种不均等的温度暴露。一个主要变量，但可以控制的变量，是倾注接种琼脂与将含抗生素的滤纸片应用于平板之间的时间间隔变化。凝固时间的这种影响以及其他几个连续操作的影响被合并为一个复合变量。然后，通过在大约100个平板的序列中插入用参考溶液设置的“外部”参考平板来考虑并归一化这个变量。不使用“内部”参考区域。对倾注琼脂的体积、培养皿中琼脂的楔形、稀释中的体积误差以及时间因素等进行了研究和讨论。本研究结果构成了后续论文中提出的测试方案的基础。
