Sharifi-Rad J, Soufi L, Ayatollahi S A M, Iriti M, Sharifi-Rad M, Varoni E M, Shahri F, Esposito S, Kuhestani K, Sharifi-Rad M
Zabol University of Medical Sciences Zabol Medicinal Plants Research Center Zabol Iran.
Guilan University of Medical Sciences Rasht Iran.
Cell Mol Biol (Noisy-le-grand). 2016 Sep 19;62(9):69-74.
Shiga toxin-producing Escherichia coli (STEC) serotype O157:H7 is one of the most important human pathogenic microorganisms, which can cause life-threatening infections. Xanthium strumarium L. is a plant with anti-bacterial activity against gram-negative and gram-positive bacteria. This study aims to demonstrate in vitro efficacy of the essential oil (EO) extracted from Xanthium strumarium L. against E. coli O157:H7. Using the agar test diffusion, the effect of Xanthium strumarium L. EO (5, 10, 15, 30, 60, and 120 mg/mL) was verified at each of the four different growth phases of E. coli O157:H7. Cell counts of viable cells and colony forming unit (CFU) were determined at regular time points using Breed's method and colony counting method, respectively. No viable cell was detectable after the 1 hour-exposure to X. strumarium EO at 30, 60, and 120 mg/mL concentrations. No bacterial colony was formed after 1 h until the end of the incubation period at 24 h. At lower concentrations, the number of bacteria cells decreased and colonies could be observed only after incubation. At the exponential phase, the EO at 15 mg/mL was only bacteriostatic, while from 30 mg/mL started to be bactericidal. X. strumarium EO antibacterial activity against Shiga toxin-producing E. coli O157:H7 is dependent on EO concentration and physiological state of the microorganisms tested. The best inhibitory activity was achieved during the late exponential and the stationary phases.
产志贺毒素大肠杆菌（STEC）血清型O157:H7是最重要的人类病原微生物之一，可引发危及生命的感染。苍耳是一种对革兰氏阴性菌和革兰氏阳性菌均具有抗菌活性的植物。本研究旨在证明从苍耳中提取的精油（EO）对大肠杆菌O157:H7的体外抗菌效果。采用琼脂扩散试验，在大肠杆菌O157:H7的四个不同生长阶段分别验证了苍耳EO（5、10、15、30、60和120mg/mL）的作用。分别使用布里德氏法和菌落计数法在固定时间点测定活细胞的细胞计数和菌落形成单位（CFU）。在30、60和120mg/mL浓度下，用苍耳EO处理1小时后未检测到活细胞。在1小时后直至24小时孵育期结束均未形成细菌菌落。在较低浓度下，细菌细胞数量减少，仅在孵育后才能观察到菌落。在指数期，15mg/mL的EO仅具有抑菌作用，而从30mg/mL开始具有杀菌作用。苍耳EO对产志贺毒素大肠杆菌O157:H7的抗菌活性取决于EO浓度和受试微生物的生理状态。在指数后期和稳定期实现了最佳抑制活性。
