Miladi Hanene, Zmantar Tarek, Kouidhi Bochra, Chaabouni Yassine, Mahdouani Kacem, Bakhrouf Amina, Chaieb Kamel
Laboratory of Analysis, Treatment and Valorization of Pollutants of the Environment and Products, Faculty of Pharmacy, Rue Avicenne, Monastir University, Tunisia.
College of Applied Medical Sciences, Medical Laboratory Department, Yanbu el Bahr, Taibah University, Al Madinah Al Monawarah, Saudi Arabia.
Microb Pathog. 2017 Mar;104:56-63. doi: 10.1016/j.micpath.2017.01.012. Epub 2017 Jan 3.
The Aims of the study was to evaluate the antibacterial susceptibility and the biofilm eradication of three natural compounds carvacrol (CAR), thymol (TH) and eugenol (EUG), alone or in combination with nalidixic acid (NA) against twelve Salmonella Typhimurium strains. The minimum inhibitory concentration (MIC) and the minimum biofilm eradication concentration (BEC) of the tested compounds (CAR, TH and EUG) and their combinations with NA were evaluated. In order to assess whether these bacteria had active efflux pumps, ethidium bromide (EtBr) accumulation assays was achieved using spectrophotometric accumulation assays. Moreover, scanning electron microscopy was used to visualize the bacterial biofilm formation on stainless steel surfaces after exposed to NA, CAR, TH and EUG alone and in combination. TH was the most effective essential oil, with the lowest MICs values ranging from 32 to 128 μg/mL followed by EUG and CAR. In addition, the combination of NA with the different compounds enhances antibiotic susceptibility of the tested bacterial strains. These results were confirmed by EtBr accumulation assays. A pronounced effect in decreasing biofilm mass was also noticed. Moreover, SEM revealed that bacterial membrane was disrupted and a complete loss of membrane integrity was also evident. The combination of natural compounds with antibiotic enhances bacterial susceptibility to NA. This combination ameliorates eradication of biofilm formed by S. Typhimurium on polystyrene microtitre plates. Additionally, this synergy induces an alteration of the bacterial cell surface visualized by SEM.
本研究的目的是评估三种天然化合物香芹酚（CAR）、百里香酚（TH）和丁香酚（EUG）单独或与萘啶酸（NA）联合使用对12株鼠伤寒沙门氏菌的抗菌敏感性和生物膜清除能力。评估了受试化合物（CAR、TH和EUG）及其与NA组合的最低抑菌浓度（MIC）和最低生物膜清除浓度（BEC）。为了评估这些细菌是否具有活性外排泵，使用分光光度法积累试验进行了溴化乙锭（EtBr）积累试验。此外，扫描电子显微镜用于观察单独和联合暴露于NA、CAR、TH和EUG后不锈钢表面上细菌生物膜的形成情况。TH是最有效的精油，最低MIC值范围为32至128μg/mL，其次是EUG和CAR。此外，NA与不同化合物的组合增强了受试菌株的抗生素敏感性。这些结果通过EtBr积累试验得到证实。还注意到在减少生物膜量方面有显著效果。此外，扫描电子显微镜显示细菌膜被破坏，膜完整性也完全丧失。天然化合物与抗生素的组合增强了细菌对NA的敏感性。这种组合改善了鼠伤寒沙门氏菌在聚苯乙烯微量滴定板上形成的生物膜的清除。此外，这种协同作用导致通过扫描电子显微镜观察到的细菌细胞表面发生改变。
