纳米技术正在研究其改善人类健康的纳米医学的潜力。本研究的目的是分离产生碳青霉烯酶的革兰氏阴性杆菌 (CPGB),研究碳青霉烯酶抗性基因的存在,确定它们的抗菌谱和生物合成银纳米粒子 (Ag NPs) 的能力,并评估鲍曼不动杆菌的抗菌活性- CPGB 上单独生物合成的 Ag NPs 以及与抗生素的组合。从研究中的各种标本中分离出总共 51 个 CPGB。自动化 Vitek-2 系统用于识别和测试这些菌株的抗菌敏感性。使用聚合酶链反应 (PCR) 鉴定了碳青霉烯酶抗性基因。根据 CPGB,A. baumannii可以生物合成 Ag NPs。X 射线衍射 (XRD)、傅立叶变换红外光谱 (FT-IR)、透射电子显微镜 (TEM) 和场发射扫描电子用于表征 Ag NP。使用微量肉汤稀释法测定 Ag NP 单独和与抗生素联合使用对 CPGB 的抗菌活性,并使用棋盘法测定它们的协同作用。bla NDM和bla OXA-48是最常见的报道,90% 的分离株产生多种碳青霉烯酶基因。替加环素被证明是最有效的抗 CPGB 抗生素。具有更多耐药基因的分离株对抗生素的耐药性更强,具有三个基因的分离株 (42%) 具有最广泛的耐药模式 (38%)。在遗传和抗生素抗性模式之间发现了重要的关系。只有鲍曼不动杆菌从所有测试的分离物中产生了 Ag NPs。通过紫外-可见光谱、FT-IR、XRD 和 TEM 分析证实了尺寸为 10 nm 的 Ag NPs。Ag NPs 对 CPGB 有效,最低抑制浓度平均为 64 至 8 μg/ml。令人惊讶的是,Ag NPs 和抗生素的组合表现出对 CPGB 的协同和部分协同活性(部分抑制浓度在 0.13 和 0.56 之间),以及抗生素浓度的显着降低,特别是在A. baumanii与头孢曲松(1024 至0.56)的情况下4微克/毫升)。Ag NPs 与抗生素的显着协同活性代表了一种有价值的纳米药物,可能在未来作为一种联合疗法找到临床应用。
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Synergistic antibacterial activity of silver nanoparticles biosynthesized by carbapenem-resistant Gram-negative bacilli
Nanotechnology is being investigated for its potential to improve nanomedicine for human health. The purpose of this study was to isolate carbapenemase-producing Gram-negative bacilli (CPGB), investigate the presence of carbapenemase resistance genes, determine their antibiogram and ability to biosynthesise silver nanoparticles (Ag NPs), and estimate the antibacterial activity of Acinetobacter baumannii-biosynthesised Ag NPs on CPGB alone and in combination with antibiotics. A total of 51 CPGBs were isolated from various specimens in the study. The automated Vitek-2 system was used to identify and test these strains' antimicrobial susceptibilities. The carbapenemase resistance genes were identified using a polymerase chain reaction (PCR). Under the CPGB, A. baumannii could biosynthesise Ag NPs. X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), and field emission scanning electron were used to characterise Ag NPs. The antibacterial activity of Ag NP alone and in combination with antibiotics against CPGB was determined using the broth microdilution method, and their synergistic effect was determined using the checkerboard assay. bla NDM and bla OXA-48 were the most commonly reported, and 90% of the isolates produced multiple carbapenemase genes. Tigecycline proved to be the most effective anti-CPGB antibiotic. Isolates with more resistance genes were more resistant to antibiotics, and isolates with three genes (42%) had the most extensively drug-resistant patterns (38%). A significant relationship was discovered between genetic and antibiotic resistance patterns. Only A. baumannii produced Ag NPs out of all the isolates tested. Ag NPs with a size of 10 nm were confirmed by UV–visible spectroscopy, FT-IR, XRD, and TEM analysis. The Ag NPs were effective against CPGB, with minimum inhibitory concentrations ranging from 64 to 8 μg/ml on average. Surprisingly, the combination of Ag NPs and antibiotics demonstrated synergistic and partial synergistic activity (fractional inhibitory concentration between 0.13 and 0.56) against CPGB, as well as a significant reduction in antibiotic concentrations, particularly in the case of A. baumanii versus ceftriaxone (1024 to 4 μg/ml). The notable synergistic activity of Ag NPs with antibiotics represents a valuable nanomedicine that may find clinical application in the future as a combined remedy.