Ong Teik Hwa, Chitra Ebenezer, Ramamurthy Srinivasan, Siddalingam Rajinikanth Paruvathanahalli, Yuen Kah Hay, Ambu Stephen Periathamby, Davamani Fabian
School of Postgraduate Studies, International Medical University, Bukit Jalil, Kuala Lumpur, Malaysia.
Division of Applied Biomedical Science and Biotechnology, School of Health Sciences, International Medical University, Bukit Jalil, Kuala Lumpur, Malaysia.
PLoS One. 2017 Mar 31;12(3):e0174888. doi: 10.1371/journal.pone.0174888. eCollection 2017.
Propolis obtained from bee hives is a natural substance with antimicrobial properties. It is limited by its insolubility in aqueous solutions; hence ethanol and ethyl acetate extracts of Malaysian propolis were prepared. Both the extracts displayed antimicrobial and anti-biofilm properties against Enterococcus faecalis, a common bacterium associated with hospital-acquired infections. High performance liquid chromatography (HPLC) analysis of propolis revealed the presence of flavonoids like kaempferol and pinocembrin. This study investigated the role of propolis developed into nanoparticles with chitosan for its antimicrobial and anti-biofilm properties against E. faecalis. Bacteria that grow in a slimy layer of biofilm are resistant to penetration by antibacterial agents. The use of nanoparticles in medicine has received attention recently due to better bioavailability, enhanced penetrative capacity and improved efficacy. A chitosan-propolis nanoformulation was chosen based on ideal physicochemical properties such as particle size, zeta potential, polydispersity index, encapsulation efficiency and the rate of release of the active ingredients. This formulation inhibited E. faecalis biofilm formation and reduced the number of bacteria in the biofilm by ~90% at 200 μg/ml concentration. When tested on pre-formed biofilms, the formulation reduced bacterial number in the biofilm by ~40% and ~75% at 200 and 300 μg/ml, respectively. The formulation not only reduced bacterial numbers, but also physically disrupted the biofilm structure as observed by scanning electron microscopy. Treatment of biofilms with chitosan-propolis nanoparticles altered the expression of biofilm-associated genes in E. faecalis. The results of this study revealed that chitosan-propolis nanoformulation can be deemed as a potential anti-biofilm agent in resisting infections involving biofilm formation like chronic wounds and surgical site infections.
从蜂巢中获取的蜂胶是一种具有抗菌特性的天然物质。它因在水溶液中不溶而受到限制；因此制备了马来西亚蜂胶的乙醇和乙酸乙酯提取物。这两种提取物对粪肠球菌均表现出抗菌和抗生物膜特性，粪肠球菌是一种与医院获得性感染相关的常见细菌。蜂胶的高效液相色谱（HPLC）分析显示存在黄酮类化合物，如山奈酚和松属素。本研究调查了用壳聚糖制成纳米颗粒的蜂胶对粪肠球菌的抗菌和抗生物膜特性的作用。生长在生物膜黏液层中的细菌对抗菌剂的渗透具有抗性。由于具有更好的生物利用度、增强的穿透能力和提高的疗效，纳米颗粒在医学上的应用最近受到了关注。基于理想的物理化学性质，如粒径、zeta电位、多分散指数、包封效率和活性成分的释放速率，选择了壳聚糖 - 蜂胶纳米制剂。该制剂在200μg/ml浓度下抑制了粪肠球菌生物膜的形成，并使生物膜中的细菌数量减少了约90%。当在预先形成的生物膜上进行测试时，该制剂在200和300μg/ml浓度下分别使生物膜中的细菌数量减少了约40%和75%。该制剂不仅减少了细菌数量，而且如通过扫描电子显微镜观察到的那样，还物理破坏了生物膜结构。用壳聚糖 - 蜂胶纳米颗粒处理生物膜改变了粪肠球菌中与生物膜相关基因的表达。本研究结果表明，壳聚糖 - 蜂胶纳米制剂可被视为一种潜在的抗生物膜剂，用于抵抗涉及生物膜形成的感染，如慢性伤口和手术部位感染。
