Department of Physics, Assam University, Silchar, 788011, India.
Department of Microbiology, Assam University, Silchar, 788011, India.
Sci Rep. 2018 Jan 9;8(1):201. doi: 10.1038/s41598-017-18590-6.
In this report, spherical silver nanoparticle (AgNP-sp) and rod-shaped silver nanoparticle (AgNR) were prepared by chemical reduction method and their antibacterial activity against various Gram-positive and Gram-negative bacteria had been evaluated for their efficiency. Minimal inhibitory concentration (MIC) tests were conducted to study the antibacterial properties, and substantiated with killing kinetics of silver nanoparticles (AgNPs). The study revealed that both AgNP-sp and AgNRs are good antibacterial candidates. Bacterial sensitivity to nanoparticles (NPs) was found to vary depending on microbial species. Disc diffusion studies revealed the greater effectiveness of AgNP-sp and AgNR against Klebsiella pneumoniae AWD5 at the doses of 249 and 392 µg. The dose dependent activities of prepared NPs were also observed on the batch studies of disc diffusion and MIC with various strains. The optical and morphological structures of NPs were analyzed by UV-visible, XRD, FE-SEM and TEM. Further, FESEM of bacterial culture treated with AgNPs confirmed antibacterial activity of NPs by showing rupture of bacterial cell wall. Also, the genome of test organism was found to have CusCFBA and CusRS operons. The killing kinetics confirmed that the death rate of K. pneumoniae was higher against AgNP-sp as compared to AgNR.
在本报告中，采用化学还原法制备了球形银纳米粒子（AgNP-sp）和棒状银纳米粒子（AgNR），并评价了它们对各种革兰氏阳性菌和革兰氏阴性菌的抗菌活性。通过最小抑菌浓度（MIC）测试研究了抗菌性能，并结合银纳米粒子（AgNPs）的杀菌动力学进行了验证。研究表明，AgNP-sp 和 AgNR 都是很好的抗菌候选物。发现细菌对纳米粒子（NPs）的敏感性取决于微生物种类。圆盘扩散研究表明，AgNP-sp 和 AgNR 在 249 和 392 μg 剂量下对肺炎克雷伯菌 AWD5 的效果更好。在圆盘扩散和 MIC 的分批研究中，也观察到了所制备 NPs 的剂量依赖性活性。通过紫外-可见分光光度计、XRD、FE-SEM 和 TEM 分析了 NPs 的光学和形态结构。此外，用 AgNPs 处理的细菌培养物的 FESEM 证实了 NPs 的抗菌活性，表明细菌细胞壁破裂。此外，测试生物的基因组中发现了 CusCFBA 和 CusRS 操纵子。杀菌动力学证实，与 AgNR 相比，肺炎克雷伯菌对 AgNP-sp 的死亡率更高。
