Department of Biology, Rasht Branch, Islamic Azad University, 4147654919, Rasht, Iran.
Department of Chemistry, Faculty of Sciences, University of Guilan, P.O. Box 41335-1914, 4199613776, Rasht, Iran.
Chem Biodivers. 2020 Jun;17(6):e2000072. doi: 10.1002/cbdv.202000072. Epub 2020 May 28.
Activity of norA efflux pump has been known as a resistance mechanism to antibiotics like ciprofloxacin in Staphylococcus aureus. This study was carried out to assess the effect of biosynthesized NiFe O @Ag nanocomposite on expression of norA gene in Staphylococcus aureus. In this experimental study, 30 clinical samples were collected from patients hospitalized at different hospitals in Guilan Province, Iran. Then, clinical isolates of S. aureus were identified by standard microbiological tests. Antimicrobial susceptibility tests of clinical and standard strains of S. aureus were done by disk diffusion method according to CLSI guideline. Fourier transform infrared spectroscopy (FT-IR) was used to analyze the various functional groups present in the biosynthesized NiFe O @Ag nanocomposite. This analysis confirmed the formation of alga proteins coated on magnetite nanocomposite. X-ray diffraction (XRD) verified the crystalline structure of NiFe O @Ag and the deposition of silver on the surface of NiFe O . Energy dispersive X-ray mapping (EDX-map) analysis confirmed the existence of Ag, Ni, Fe and O in the final product. Scanning electron microscopy (SEM) confirmed that the nanocomposites were spherical in shape and Transmission electron microscopy (TEM) results revealed that the NiFe O @Ag had the particle size about 100 nm. Antibacterial activity of NiFe O @Ag alone and combined with ciprofloxacin was evaluated using the disk assay method, and minimum inhibitory concentration (MIC) by broth dilution method. Afterwards, the expression of norA efflux pump gene with and without of NiFe O @Ag nanocomposite and ciprofloxacin was evaluated by Real-Time PCR. Real-Time PCR results demonstrated that the expression of norA gene in the strains exposed to both NiFe O @Ag nanocomposite (1/4 MIC) and ciprofloxacin (1/8 MIC) significantly reduced in comparison to untreated strains. This study reveals that, when NiFe O @Ag nanocomposite is combined with ciprofloxacin, the inhibitory effect of ciprofloxacin increases against growth of S. aureus. Therefore, NiFe O @Ag nanocomposite can be considered as an effective factor to decrease the growth of S. aureus along with ciprofloxacin.
已有研究表明，葡萄球菌中 norA 外排泵的活性是对抗环丙沙星等抗生素的一种耐药机制。本研究旨在评估生物合成的 NiFeO@Ag 纳米复合材料对金黄色葡萄球菌 norA 基因表达的影响。
在这项实验研究中，从伊朗吉兰省不同医院住院的患者中采集了 30 份临床样本。然后，通过标准微生物学试验鉴定临床分离的金黄色葡萄球菌。按照 CLSI 指南，采用纸片扩散法对临床和标准金黄色葡萄球菌株进行抗生素敏感性试验。傅里叶变换红外光谱（FT-IR）用于分析生物合成的 NiFeO@Ag 纳米复合材料中存在的各种官能团。该分析证实了藻蛋白覆盖在磁铁矿纳米复合材料上的形成。X 射线衍射（XRD）证实了 NiFeO@Ag 的结晶结构和银在 NiFeO 表面的沉积。能量色散 X 射线映射（EDX-map）分析证实了最终产物中 Ag、Ni、Fe 和 O 的存在。扫描电子显微镜（SEM）证实纳米复合材料呈球形，透射电子显微镜（TEM）结果表明 NiFeO@Ag 的粒径约为 100nm。采用纸片法评估 NiFeO@Ag 单独使用和与环丙沙星联合使用的抗菌活性，采用肉汤稀释法评估最小抑菌浓度（MIC）。然后，通过 Real-Time PCR 评估 NiFeO@Ag 纳米复合材料和环丙沙星对 norA 外排泵基因表达的影响。Real-Time PCR 结果表明，与未处理的菌株相比，暴露于 NiFeO@Ag 纳米复合材料（1/4MIC）和环丙沙星（1/8MIC）的菌株中 norA 基因的表达显著降低。
这项研究表明，当 NiFeO@Ag 纳米复合材料与环丙沙星联合使用时，环丙沙星对金黄色葡萄球菌生长的抑制作用增强。因此，NiFeO@Ag 纳米复合材料可以被认为是一种有效的因素，可与环丙沙星一起降低金黄色葡萄球菌的生长。
