Development of multidrug resistance among pathogens has become a global problem for chemotherapy of bacterial infections. Extended-spectrum β-lactamase- (ESβL-) producing enteric bacteria and methicillin-resistant Staphylococcus aureus (MRSA) are the two major groups of problematic MDR bacteria that have evolved rapidly in the recent past. In this study, the aqueous extract of Murraya koenigii leaves was used for synthesis of silver nanoparticles. The synthesized MK-AgNPs were characterized using UV-vis spectroscopy, FTIR, XRD, SEM, and TEM, and their antibacterial potential was evaluated on multiple ESβL-producing enteric bacteria and MRSA. The nanoparticles were predominantly found to be spheroidal with particle size distribution in the range of 5–20 nm. There was 60.86% silver content in MK-AgNPs. Evaluation of antibacterial activity by the disc-diffusion assay revealed that MK-AgNPs effectively inhibited the growth of test pathogens with varying sized zones of inhibition. The MICs of MK-AgNPs against both MRSA and methicillin-sensitive S. aureus (MSSA) strains were 32 μg/ml, while for ESβL-producing E. coli, it ranged from 32 to 64 μg/ml. The control strain of E. coli (ECS) was relatively more sensitive with an MIC of 16 μg/ml. The MBCs were in accordance with the respective MICs. Analysis of growth kinetics revealed that the growth of all tested S. aureus strains was inhibited (∼90%) in presence of 32 μg/ml of MK-AgNPs. The sensitive strain of E. coli (ECS) showed least resistance to MK-AgNPs with >81% inhibition at 16 μg/ml. The present investigation revealed an encouraging result on in vitro efficacy of green synthesized MK-AgNPs and needed further in vivo assessment for its therapeutic efficacy against MDR bacteria.

中文翻译：

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利用Murraya koenigii（L.）合成的银纳米颗粒对耐多药病原菌的抗菌作用。

病原体之间多药耐药性的发展已成为细菌感染化学疗法的全球性问题。超广谱β -lactamase-（ES β L-）生产肠道细菌，耐甲氧西林金黄色葡萄球菌（MRSA）是有问题的MDR细菌已经在最近的过去迅速发展的两大群体。在这项研究中，墨兰叶的水提取物用于合成银纳米颗粒。使用UV-Vis光谱，FTIR，XRD，SEM，TEM和，和它们的抗菌潜力上的多个ES评估所合成的MK-的AgNPs进行表征β产生L的肠细菌和MRSA。主要发现纳米颗粒为球形，粒径分布范围为5–20 nm。MK-AgNPs中的银含量为60.86％。通过椎间盘扩散试验评估抗菌活性表明，MK-AgNPs有效抑制了测试病原体的生长，并具有不同大小的抑制区。对两种MRSA MK-的AgNPs和甲氧西林敏感的MIC的金黄色葡萄球菌（MSSA）菌株32  μ微克/毫升，而对ES β L-生产大肠杆菌，它的范围为32〜64  μ微克/毫升。大肠杆菌（ECS）的对照菌株相对敏感，MIC为 16μ克/毫升 MBC符合各自的MIC。生长动力学的分析显示，所有测试的生长的金黄色葡萄球菌菌株中的32存在的抑制（〜90％）  μ微克/毫升MK-的AgNPs的。的敏感性菌株大肠杆菌（ECS）显示出对MK-的AgNPs具有> 81％的抑制率至少阻力为16  μ微克/毫升。本研究揭示了绿色合成的MK-AgNPs的体外功效令人鼓舞的结果，需要进一步体内评估其抗MDR细菌的功效。