Department of Microbiology and Molecular Genetics, The Women University, Multan, Pakistan.
School of Environmental Studies, China University of Geosciences, Wuhan, China.
Environ Sci Pollut Res Int. 2020 Oct;27(30):37347-37356. doi: 10.1007/s11356-020-07610-0. Epub 2020 Mar 4.
Silver nanoparticles are potent antimicrobials and could be used as a promising alternative of conventional antibiotics. The aim of this study was to isolate bacteria from soil that have ability to produce AgNPs by secondary metabolite activity and their elucidation against human pathogens. These strains Escherichia coli, Exiguobacterium aurantiacumm, and Brevundimonas diminuta with NCBI accession number MF754138, MF754139, and MF754140 respectively were grown for secondary metabolite production. The nanoparticles were confirmed and characterized by UV-Vis spectroscopy and transmission electron microscopy. The optimization study was also carried out to obtain the maximum production of silver nanoparticles. Three parameters, temperature, pH, and AgNO3 concentration, were used to optimize the production of silver nanoparticles. Antimicrobial potential of these nanoparticles was addressed on the Muller-Hinton Agar, and their zones of inhibitions were measured. TEM analysis revealed the size and shape of the silver nanoparticles. All types of AgNPs were spherical in shape; their size range is from 5 to 50 nm. The findings of optimization study showed the maximum production of silver nanoparticles at the pH 9, temperature 37 °C, and 1 mM AgNO3 concentration. All the strains exhibited the great potential as antimicrobial agents against MRSA and several other MDR bacteria with minimum 10 mm to maximum 28 mm zone of inhibition. It was concluded that the present study is an eco-friendly approach for the synthesis of AgNPs that will be beneficial to control the nosocomial infections triggered by MRSA and other human pathogens.
银纳米粒子是有效的抗菌剂，可作为传统抗生素的有前途替代品。本研究的目的是从土壤中分离出具有通过次生代谢产物活性产生 AgNPs 的能力的细菌，并对其进行阐明以对抗人类病原体。这些菌株大肠杆菌、橙色极端杆菌和微弱苍白杆菌，其 NCBI 登录号分别为 MF754138、MF754139 和 MF754140，用于次生代谢产物的产生。通过紫外-可见光谱和透射电子显微镜对纳米粒子进行了确认和表征。还进行了优化研究以获得最大量的银纳米粒子生产。使用三个参数，温度、pH 和 AgNO3 浓度，优化了银纳米粒子的生产。这些纳米粒子的抗菌潜力在 Muller-Hinton 琼脂上进行了评估，并测量了它们的抑菌区。TEM 分析揭示了银纳米粒子的大小和形状。所有类型的 AgNPs 均呈球形，其尺寸范围为 5 至 50nm。优化研究的结果表明，在 pH9、温度 37°C 和 1mM AgNO3 浓度下，银纳米粒子的产量最大。所有菌株都表现出作为抗菌剂对抗 MRSA 和其他几种 MDR 细菌的巨大潜力，抑菌区最小为 10mm，最大为 28mm。结论是，本研究是一种绿色环保的 AgNPs 合成方法，将有利于控制由 MRSA 和其他人类病原体引发的医院感染。
