Department of Microbiology, Faculty of Sciences, Neyshabur Branch, Islamic Azad University, Neyshabur, Iran.
Biol Trace Elem Res. 2020 Sep;197(1):330-340. doi: 10.1007/s12011-019-01962-6. Epub 2019 Nov 7.
Carbapenem-resistant Acinetobacter baumannii (CRAB) remains as a serious cause of infectious diseases and septic mortality in hospitalized patients worldwide. This study was conducted to evaluate the antimicrobial effect of imipenem conjugated silver nanoparticles (AgNPs) on resistant isolated A. baumannii from nosocomial infections.The antimicrobial susceptibility test of 100 A. baumannii clinical isolates against different antibiotics was performed. PCR was used to confirm bacterial resistance and to identify different genes encoding Ambler class β-lactamases. The chemically synthesized AgNPs were characterized using UV-vis spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), and Fourier-transform infrared (FTIR). The stability, drug release kinetic, and cytotoxicity (MTT assay) of AgNPs were also investigated. The imipenem were conjugated with AgNPs, and conjugants were characterized as discussed above. Minimum inhibitory concentration (MIC) of the AgNPs and conjugants were tested against A. baumannii isolates and compared with imipenem alone.The results revealed that among all isolated A. baumannii, 76% showed resistant to imipenem (MIC ≥ 64 μg/mL to ≥ 256 μg/mL). The bla, bla, bla, and bla genes were the most prevalent genes. UV-vis spectroscopy, XRD, TEM, and FTIR analysis confirmed synthesis of AgNPs (average size of 10-40 nm) and conjugation with imipenem. The release of imipenem from AgNPs can be defined as Fickian diffusion model. The MIC values of AgNPs conjugated with imipenem against resistant A. baumannii were decreased in a dose dependent manner and were based on existence of resistant genes. The AgNPs also showed low cytotoxic effects.The results suggest that imipenem-AgNPs has a strong potency as a powerful antibacterial agent against multi-resistant A. baumannii.
耐碳青霉烯鲍曼不动杆菌（CRAB）仍然是全球住院患者感染性疾病和败血症死亡率的严重原因。本研究旨在评估亚胺培南结合银纳米粒子（AgNPs）对医院感染中分离的耐碳青霉烯鲍曼不动杆菌的抗菌作用。对 100 株耐碳青霉烯鲍曼不动杆菌临床分离株进行了不同抗生素的抗菌敏感性试验。采用 PCR 方法确认细菌耐药性，并鉴定不同基因编码的 Ambler 类β-内酰胺酶。采用紫外可见分光光度法、X 射线衍射（XRD）、透射电子显微镜（TEM）和傅里叶变换红外（FTIR）对化学合成的 AgNPs 进行了表征。还研究了 AgNPs 的稳定性、药物释放动力学和细胞毒性（MTT 测定）。将亚胺培南与 AgNPs 偶联，并对偶联物进行了上述特征描述。对 AgNPs 和偶联物进行了 MIC 测试，以测试对耐碳青霉烯鲍曼不动杆菌分离株的抗菌作用，并与单独使用亚胺培南进行了比较。结果表明，在所分离的耐碳青霉烯鲍曼不动杆菌中，76%对亚胺培南耐药（MIC 值为 64μg/ml 至 256μg/ml）。bla、bla、bla 和 bla 基因是最常见的基因。紫外可见分光光度法、XRD、TEM 和 FTIR 分析证实了 AgNPs 的合成（平均粒径为 10-40nm）和与亚胺培南的偶联。AgNPs 中亚胺培南的释放可以定义为菲克扩散模型。亚胺培南结合 AgNPs 对耐药鲍曼不动杆菌的 MIC 值呈剂量依赖性降低，这与耐药基因的存在有关。AgNPs 也表现出较低的细胞毒性。结果表明，亚胺培南-AgNPs 作为一种强大的抗菌剂，对多耐药鲍曼不动杆菌具有很强的杀菌作用。
