King Thea, Dykes Gary, Kristianti Ruth
Food Science Australia, Cnr Creek and Wynnum Rds, Cannon Hill, QLD4170, Australia.
J AOAC Int. 2008 Nov-Dec;91(6):1423-9.
A comparison was made to evaluate the ability of the most commonly used qualitative agar diffusion methods and a quantitative broth dilution assay to determine the antimicrobial activity of a plant extract and a variety of phenolic compounds. A disc and well diffusion technique and a microtiter broth microdilution (MBM) assay were used as antimicrobial susceptibility tests of a plant extract and several phenolic compounds against 7 bacterial species. In both the well and disc diffusion assays, the level of reproducibility was poor and a linear or logarithmic relationship did not exist between inhibition zone size and the concentration of the agents. The MBM method produced the most consistent results and allowed the determination of the relative sensitivities of each species and the relative antimicrobial activities of each agent. This study demonstrated that when a diffusion method is used, multiple concentrations of the agent must be assayed to ensure that a relationship exists between the concentration of the agent and inhibition zone size. When a relationship does not exist, antimicrobial activity should be determined by a quantitative dilution technique.
进行了一项比较，以评估最常用的定性琼脂扩散法和定量肉汤稀释法测定植物提取物和多种酚类化合物抗菌活性的能力。采用纸片扩散法和打孔扩散法以及微量肉汤稀释（MBM）试验作为植物提取物和几种酚类化合物对7种细菌的药敏试验。在打孔扩散法和纸片扩散法中，重现性水平较差，抑菌圈大小与药物浓度之间不存在线性或对数关系。MBM法产生的结果最一致，能够确定每种细菌的相对敏感性以及每种药物的相对抗菌活性。本研究表明，当使用扩散法时，必须检测药物的多个浓度，以确保药物浓度与抑菌圈大小之间存在关系。当不存在这种关系时，应通过定量稀释技术测定抗菌活性。
