Iseppi Ramona, Mariani Martina, Condò Carla, Sabia Carla, Messi Patrizia
Department of Life Sciences, University of Modena and Reggio Emilia, Via G. Campi 103/287, 41125 Modena, Italy.
Antibiotics (Basel). 2021 Apr 10;10(4):417. doi: 10.3390/antibiotics10040417.
The emergence of antibiotic-resistant bacteria has become a major concern worldwide. This trend indicates the need for alternative agents to antibiotics, such as natural compounds of plant origin. Using agar disc diffusion and minimum inhibitory concentration (MIC) assays, we investigated the antimicrobial activity of (AEO), (LEO), (EEO), (TTO), and (CEO) essential oils (EOs) against three representatives of antibiotic-resistant pathogens and respective biofilms: vancomycin-resistant enterococci (VRE), methicillin-resistant (MRSA), and extended-spectrum β-lactamase (ESBL)-producing . Using the checkerboard method, the efficacy of the EOs alone, in an association with each other, or in combination with the reference antibiotics was quantified by calculating fractional inhibitory concentrations (FICs). All the EOs displayed antibacterial activity against all strains to different extents, and TTO was the most effective. The results of the EO-EO associations and EO-antibiotic combinations clearly showed a synergistic outcome in most tests. Lastly, the effectiveness of EOs both alone and in association or combination against biofilm formed by the antibiotic-resistant strains was comparable to, and sometimes better than, that of the reference antibiotics. In conclusion, the combination of EOs and antibiotics represents a promising therapeutic strategy against antibiotic-resistant bacteria, even protected inside biofilms, which can allow decreasing the concentrations of antibiotics used.
抗生素耐药细菌的出现已成为全球主要关注的问题。这一趋势表明需要抗生素的替代药物，例如植物来源的天然化合物。我们使用琼脂扩散法和最低抑菌浓度（MIC）测定法，研究了香芹酚精油（AEO）、月桂叶精油（LEO）、桉叶精油（EEO）、百里香酚精油（TTO）和肉桂精油（CEO）对三种耐药病原体及其生物膜代表菌株的抗菌活性：耐万古霉素肠球菌（VRE）、耐甲氧西林金黄色葡萄球菌（MRSA）以及产超广谱β-内酰胺酶（ESBL）的大肠埃希菌。使用棋盘法，通过计算分数抑菌浓度（FIC）来量化单独使用精油、精油相互组合或精油与参考抗生素组合的疗效。所有精油均对所有菌株表现出不同程度的抗菌活性，其中百里香酚精油最有效。精油-精油组合以及精油-抗生素组合的结果在大多数试验中均明显显示出协同效应。最后，精油单独使用、组合使用或联合使用对耐药菌株形成的生物膜的有效性与参考抗生素相当，有时甚至优于参考抗生素。总之，精油与抗生素的组合代表了一种针对耐药细菌的有前景的治疗策略，即使对于生物膜内的细菌也有效，这可以降低抗生素的使用浓度。
