Khan Hanzala, Gul Anum, Najam Zainab, Malik Taqdees
Dow College of Biotechnology, Dow University of Health Sciences, Karachi, Pakistan.
Department of Microbiology, Jinnah University for Women, Karachi, Pakistan.
Sci Rep. 2025 May 28;15(1):18742. doi: 10.1038/s41598-025-01524-y.
The rise in antibiotic resistance has created an urgent need for alternative strategies to combat multidrug-resistant (MDR) bacterial infections. Silver nanoparticles (AgNPs) possess unique antibacterial properties, making them a promising option in biomedical applications. This study explores the green synthesis of silver nanoparticles (AgNPs) using Citrus sinensis peel extract and their synergistic potential with cefotaxime against multidrug-resistant (MDR) clinical isolates. For the optimization of AgNPs synthesis, Plackett-Burman experimental design (PBD) was implemented that demonstrated incubation time, temperature and extract: AgNO ratio as significant factors. The UV-Vis spectroscopy analysis revealed a characteristic absorbance peak of CS-AgNPs at 470 nm. The size of biosynthesized AgNPs was analyzed using Scanning Electron Microscopy (SEM), that showed size range of 50-60 nm with spherical shaped morphology. Fourier Transform Infrared Spectroscopy (FTIR) analysis found different functional groups involved in the stabilization and capping of AgNPs, as indicated by the peaks at 2925 cm, 1630 cm, 1100 cm and 1016 cm revealing -CH stretching aliphatic carbon, the carboxyl group, OH group and C-O-C group, respectively. The cytotoxicity of the synthesized CS-AgNPs and its synergistic effect with cefotaxime (CTX) antibiotic was analyzed with MTT assay. The combination of CS-AgNPs and CTX showed significant decrease in cytotoxicity compared to CS-AgNPs alone. Antibacterial activity of CS-AgNPs against MDR clinical isolates was performed using minimum inhibitory concentration (MIC) method. The MIC of CS-AgNPs was observed within 3.125-12.5 µg/ml range. Synergism assay of CS-AgNPs with CTX was also evaluated to determine the fractional inhibitory concentration (FIC) index. Clinical isolates (E. coli), S-11, S-14, S-16, S-19, and S-20 showed FIC in the range of 0.162-0.402 indicating synergism whereas, S-04, S-06, S-10, S-15 and S-21 showed the FIC in the range of 0.644-0.804 indicating the additive effect. The MDR E. coli clinical isolates S-11, S-16, S14, S-19 and S-20 demonstrated 65-85% biofilm inhibition which was significantly (p ≤ 0.001) high in all tested isolates. Significant (p ≤ 0.001) eradication of preformed biofilm in the range of 60-78% was also observed in S-16 clinical isolate.
抗生素耐药性的上升迫切需要替代策略来对抗多重耐药（MDR）细菌感染。银纳米颗粒（AgNPs）具有独特的抗菌特性，使其成为生物医学应用中有前景的选择。本研究探索了利用甜橙果皮提取物绿色合成银纳米颗粒（AgNPs）及其与头孢噻肟对多重耐药（MDR）临床分离株的协同潜力。为了优化AgNPs的合成，实施了Plackett-Burman实验设计（PBD），结果表明孵育时间、温度和提取物：硝酸银比例是显著因素。紫外-可见光谱分析显示CS-AgNPs在470nm处有特征吸收峰。使用扫描电子显微镜（SEM）分析生物合成的AgNPs的尺寸，结果显示尺寸范围为50-60nm，形态为球形。傅里叶变换红外光谱（FTIR）分析发现了参与AgNPs稳定和包覆的不同官能团，2925cm、1630cm、1100cm和1016cm处的峰分别表明存在-CH脂肪族碳伸缩振动、羧基、OH基团和C-O-C基团。用MTT法分析了合成的CS-AgNPs的细胞毒性及其与头孢噻肟（CTX）抗生素的协同作用。与单独的CS-AgNPs相比，CS-AgNPs与CTX的组合显示细胞毒性显著降低。采用最低抑菌浓度（MIC）法检测CS-AgNPs对MDR临床分离株的抗菌活性。观察到CS-AgNPs的MIC在3.125-12.5μg/ml范围内。还评估了CS-AgNPs与CTX的协同试验以确定分数抑菌浓度（FIC）指数。临床分离株（大肠杆菌）S-11、S-14、S-16、S-19和S-20的FIC在0.162-0.402范围内，表明具有协同作用，而S-04、S-06、S-10、S-15和S-21的FIC在0.644-0.804范围内，表明具有相加作用。多重耐药大肠杆菌临床分离株S-11、S-16、S14、S-19和S-20表现出65-85%的生物膜抑制，在所有测试分离株中显著（p≤0.001）较高。在S-16临床分离株中也观察到显著（p≤0.001）根除60-78%的预先形成的生物膜。
