Department of Life Sciences, University of Modena and Reggio Emilia, Via G. Campi 287, 41125 Modena, Italy.
Burn Intensive Care Unit, Hospital A. Cardarelli, Via A. Cardarelli 9, 80131 Naples, Italy.
Molecules. 2023 Feb 9;28(4):1671. doi: 10.3390/molecules28041671.
In the present investigation, the anti-biofilm potential of two essential oils (EOs), Chell (Tea-Tree) (TTO) and Labill. (EEO) was characterized and tested "in vitro" against both mature biofilms and biofilms in the process of formation, produced by strains belonging to three main categories of antibiotic resistant bacteria (ARB): Vancomycin-resistant enterococci (VRE), methicillin-resistant (MRSA) and broad-spectrum β-lactamase-producing (ESBL). The study was carried out in 96-well microtiter-plates using EOs alone, in association with each other and in combination with antibiotics against both single and multi-species biofilm. The study demonstrated the ability of TTO and EEO to counteract the ARB strains in sessile form, with promising results in particular against the biofilm in formation. Mature biofilm by ESBL was the most sensitive in the results from the quantification study of viable cells performed in multi-species biofilms. Lastly, in all tests, carried out using TTO/EEO associations and EOs/antibiotic combinations, the synergistic effect which emerged from the FIC-index has been confirmed, and both the reduction of biofilm in formation, and the removal of mature structure was obtained at very low concentrations, with values from 4 to >512-fold lower than the minimum inhibitory concentration (MIC) of the single compounds.
在本研究中，两种精油（茶树油和桉树油）的抗生物膜特性进行了“体外”测试，以对抗三种主要抗生素耐药菌（VRE、MRSA 和产广谱β-内酰胺酶）产生的成熟生物膜和生物膜形成过程中的生物膜。研究使用精油单独、相互联合以及与抗生素联合使用，在 96 孔微量滴定板上进行，针对单种和多种生物膜。研究表明，TTO 和 EEO 能够抑制生物膜中的 ARB 菌株，特别是在形成中的生物膜方面，效果非常显著。在多物种生物膜中进行的活菌定量研究结果表明，ESBL 产生的成熟生物膜对 TTO/EEO 联合使用和 EO/抗生素组合测试最敏感。最后，在所有使用 TTO/EEO 联合和 EO/抗生素组合进行的测试中，都证实了 FIC 指数所呈现的协同作用，在非常低的浓度下即可减少生物膜的形成和去除成熟结构，其值比单个化合物的最低抑菌浓度（MIC）低 4 至>512 倍。
