丁香酚对多重耐药大肠杆菌的抑菌活性及其作用机制研究

为研究丁香酚对多重耐药大肠杆菌(Multidrug-resistant Escherichia coli,MDR E.coli)的抑菌活性,利用微量二倍稀释法和琼脂扩散法确定丁香酚对多重耐药大肠杆菌的最低抑菌浓度(Minimum inhibitory concentration,MIC)和最低杀菌浓度(Minimum bactericidal concentration,MBC),并利用紫外分光光度法、考马斯亮蓝法等方法初步分析其作用机制。结果表明,丁香酚对MDR E.coli的MIC和MBC分别为2.50 mg/mL和5.00 mg/mL;丁香酚可延长MDR E.coli迟缓期进入对数生长期的进程,改变菌体结构,增加菌株可溶性蛋白的含量和胞外核酸的量,增大菌体培养液中的电导率,对MDR E.coli具有较强的抑菌作用,这些作用可能归因于丁香酚对其细胞结构的破坏。本研究为临床有效缓解或解决多重耐药大肠杆菌的耐药、感染和致死率等问题提供新的思路、新途径,并为其在医药和食品开发领域的应用奠定理论基础。

Antibacterial Activity and Mechanism of Eugenol against Multidrug-resistant Escherichia coli

In order to study the antibacterial activity of eugenol on multidrug-resistant Escherichia coli (MDR E.coli), the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of eugenol against MDR E.coli were determined by micro-diluted dilution method and agar diffusion method. UV spectrophotometry and the Coomassie blue method were used to analyze the antibacterial activity. The results showed that the MIC and MBC of eugenol for MDR E.coli were 2.50 mg/mL and 5.00 mg/mL, respectively. Eugenol can prolong the progression of MDR E.coli into the logarithmic growth phase, change the structure of the bacteria and increase the soluble protein content and the amount of extracellular nucleic acids of the strain. Eugenol also increased the conductivity in the culture medium. These may be attributed to the destruction effect of eugenol on cellular structure of the bacteria. The study provides a new way to overcome drug resistance, infection and mortality of MDR E.coli, and lay a theoretical foundation for the application of eugenol in medicine and food development.