Ansari Mohammad Azam, Kalam Abul, Al-Sehemi Abdullah G, Alomary Mohammad N, AlYahya Sami, Aziz Mohammad Kashif, Srivastava Shekhar, Alghamdi Saad, Akhtar Sultan, Almalki Hussain D, Adil Syed F, Khan Mujeeb, Hatshan Mohammad R
Department of Epidemic Disease Research, Institute for Research & Medical Consultations (IRMC), Imam Abdulrahman Bin Faisal University, Dammam 31441, Saudi Arabia.
Department of Chemistry, Faculty of Science, King Khalid University, Abha 61413, Saudi Arabia.
Antibiotics (Basel). 2021 Jun 16;10(6):725. doi: 10.3390/antibiotics10060725.
Biofilms not only protect bacteria and Candida species from antibiotics, but they also promote the emergence of drug-resistant strains, making eradication more challenging. As a result, novel antimicrobial agents to counteract biofilm formation are desperately needed. In this study, leaf extract (TCE) was used to optimize the TCE-capped silver nanoparticles (TCE-AgNPs) via a one-pot single-step method. Varied concentrations of TCE have yielded different sized AgNPs. The physico-chemical characterization of TCE-AgNPs using UV-Vis, SEM, TEM, FTIR, and Raman spectroscopy have confirmed the formation of nanostructures, their shape and size and plausible role of TCE bio-active compounds, most likely involved in the synthesis as well as stabilization of NPs, respectively. TCE-AgNPs have been tested for antibiofilm and antimicrobial activity against multidrug-resistant (MDR-PA), methicillin-resistant (MRSA), and using various microbiological protocols. TCE-Ag-NPs-3 significantly inhibits biofilm formation of MDR-PA, MRSA, and by 73.7, 69.56, and 63.63%, respectively, at a concentration of 7.8 µg/mL, as determined by crystal violet microtiter assay. Furthermore, SEM micrograph shows that TCE-AgNPs significantly inhibit the colonization and adherence of biofilm forming cells; individual cells with loss of cell wall and membrane integrity were also observed, suggesting that the biofilm architecture and EPS matrix were severely damaged. Moreover, TEM and SEM images showed that TCE-AgNPs brutally damaged the cell wall and membranes of MDR-PA, MRSA, and . Additionally, extreme ultrastructural changes such as deformation, disintegration, and separation of cell wall and membrane from the cells, have also been observed, indicating significant loss of membrane and cell wall integrity, which eventually led to cell death. Overall, the research revealed a simple, environmentally friendly, and low-cost method for producing colloidal TCE-AgNPs with promising applications in advanced clinical settings against broad-spectrum biofilm-forming antibiotic-resistant bacteria and candida strains.
生物膜不仅能保护细菌和念珠菌属免受抗生素影响，还会促使耐药菌株的出现，使得根除工作更具挑战性。因此，迫切需要新型抗菌剂来对抗生物膜的形成。在本研究中，通过一锅一步法使用叶提取物（TCE）优化了TCE包覆的银纳米颗粒（TCE-AgNPs）。不同浓度的TCE产生了不同尺寸的AgNPs。使用紫外可见光谱、扫描电子显微镜、透射电子显微镜、傅里叶变换红外光谱和拉曼光谱对TCE-AgNPs进行的物理化学表征证实了纳米结构的形成、它们的形状和大小以及TCE生物活性化合物可能发挥的作用，最有可能分别参与了纳米颗粒的合成以及稳定化过程。已使用各种微生物学方案对TCE-AgNPs针对多重耐药（MDR-PA）、耐甲氧西林（MRSA）以及（此处原文缺失一种细菌名称）的抗生物膜和抗菌活性进行了测试。通过结晶紫微量滴定法测定，在浓度为7.8 µg/mL时，TCE-Ag-NPs-3分别显著抑制MDR-PA、MRSA以及（此处原文缺失一种细菌名称）的生物膜形成达73.7%、69.56%和63.63%。此外，扫描电子显微镜照片显示TCE-AgNPs显著抑制生物膜形成细胞的定殖和黏附；还观察到细胞壁和细胞膜完整性丧失的单个细胞，这表明生物膜结构和胞外聚合物基质受到了严重破坏。而且，透射电子显微镜和扫描电子显微镜图像显示TCE-AgNPs严重破坏了MDR-PA、MRSA以及（此处原文缺失一种细菌名称）的细胞壁和细胞膜。此外，还观察到了诸如细胞壁和细胞膜变形、解体以及与细胞分离等极端超微结构变化，这表明细胞膜和细胞壁完整性显著丧失，最终导致细胞死亡。总体而言，该研究揭示了一种简单、环保且低成本的方法来生产胶体TCE-AgNPs，其在先进临床环境中针对广谱生物膜形成的抗生素耐药细菌和念珠菌菌株具有广阔的应用前景。
