Antimicrobial activity of silver nanoparticles biosynthesized by Streptomyces spp.

Bioproduction options for nanoparticles are becoming a highly significant subject, with environmental and economic benefits over physical and chemical processes. The purpose of the current study is to detect the antimicrobial activity of chitosan-Graphene oxide nanoparticles that include The Minimum Inhibitory Concentration (MIC) is a method of determining antibacterial activity, Antibiofilm Activity by Tissue culture plate method, Antioxidant activity, and finally the hemolysis activity of mixing nanoparticles CS-GO that synthesis biologically. the result of Antibacterial activity showed the ID50 for inhibition is at a concentration (1 mg/ml), while the Antibiofilm activity result shows the high concentration of CS-GO nanoparticles (16 mg/ml) showed the higher activity in inhibition of biofilm formation while the less concentration (0.6mg/ml) appeared very low inhibition activity on biofilm formation. The antioxidant activity of nanoparticles showed the high scavenging ability at a concentration (600 mg/ml) as (54.06%) while the less concentration (100mg/ml) appeared scavenger ability as (29.42%) also the hemolysis activity on CS-GO nanoparticles on blood showed different ability at different concentration, the preferred concentration (1mg/ml) show no hemolysis on blood.

Metals that contain nanomaterials have the potential to be employed in controlling different kinds of infection, however, very limited information is known about their antibacterial properties. This study has been done to investigate the nanosynthesis titanium nanoparticles (TiNPs) using Streptococcus thermophilus and analyzing their biological actions as antibacterial. The bacterial isolates identified using universal primers 16S rRNA; then the 16S rRNA gene nucleotide sequences were aligned with the nucleotide sequences of strains obtained from the GeneBank through the software CLUSTAL X (version 1.82). Titanium nanoparticles were nanosynthesized by adding 0.025M titanium dioxide (TiO2) into cell-free supernatant for Streptococcus thermophilus. TiO2 was used as a precursor for nanobiosynthesis TiNPs. The formation of TiNPs was indicated by the color alteration of the solution from the light brown into dark brown indicates for the production of TiNPs. The Characterization of nanobiosynthesis was accomplished with UV-Visible (absorbance at 377nm), Scanning Electron Microscope, X-ray diffraction, Atomic Force Microscope, Energy-dispersive X-ray spectroscopy was used to distinguish the dimension, form (spherical) by SEM, dispersal (homogenous) and elemental analysis of nanoparticles. Biogenic TiNPs have displayed antibacterial and antibiofilm activity against both multidrugresistant Klebsiella pneumonia and Staphylococcus aureus. As an antibacterial activity, the TiNPs inhibited significantly K.pneumoniae (20 mm) with concentration (500 μg/ml), and S. aureus (16 mm) with the same concentration and increasing the concentration of TiNPs the inhibition zone increased. While as antibiofilm activity of TiNPs using the tube method, the tubes containing bacterial suspension K.pneumoniae and S.aureus with TiNPs, the results demonstrated that the biofilm formation was prevented and removed by the effect of TiNPs.

Due to the emergence of high virulence pathogenic strains of bacteria that are resistant to most antibiotics, this study was conducted to find alternative materials for antibiotics or work with antibiotics against bacterial strains that are resistant to antibiotics. in this study, we used bacterially reduced graphene oxide (BrGO) for this purpose and through the experiment showed that Graphene oxide (GO) nanosheets can biologically reduce by Bacillus clausii by reaction GO with cell free supernatant, where the reaction mixture incubates for 72hrs at 37C° in a shaking incubator. The general properties of reduced Graphene Oxide (rGO) nanosheets by B. clausii were determined through Ultraviolet–visible (UV-vis) Spectroscopy, Scanning Electron Microscope (SEM), Energy Dispersive X-Ray Spectroscopy (EDS), Fourier Transform Infrared Spectroscopy (FTIR), Atomic Force Microscopy (AFM), and X-Ray Diffraction (XRD) analysis. The results showed the successful bacterial synthesis of rGO nanosheets via removal of water molecules and oxygen functional groups from interlayer of GO. So, the reduced Graphene oxide by Bacillus clausii considered excellent and eco-friendly. BrGO nanosheets exhibited potent noticeable antibacterial activity at different concentrations (0.1, 0.5, 1, 5, 10 mg/ml) against both Gram (-ve) and Gram (+ve) tested MDR uropathogenic isolates when used alone or at combining with other antibiotics. also the results showed that potent growth inhibition zones was increased with increasing concentrations of BrGO.

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The aim of the this study was to study the antimicrobial, antibiofilm, and antioxidant activity of Chitosan nanoparticles synthesized by E. coli. Twenty five Sample and investigations were achieved during the period from November 2018 to April 2019. Wound infection samples were collected from Two different hospital in Najaf province (AL-Sadder medical city). The A5 (E.coli) efficient isolate. the isolate was diagnosed by convenatial and molecular methods. Molecular study showed the E,coli isolate gave positive results (1270bp) for 16s rRNA assay, Data of E. coli strain at the locus (MN197856), accession (MN197856), version (MN197856.1), defined as (Escherichia coli strain Kafeel-1 16S ribosomal RNA gene, partial sequence. The results showed the gram positive bacteria highly resistante to novobiocin and nitrofurantion with the diameter of inhibition zone 27 and 20mm respectively, and low resistante to amoxicillin/calvulanic acid with the diameter of inhibition zone (0 mm). Where gram negative bacteria showed highly resistante to imipenem with the diameter of inhibition zone 22 mm. and low resistante to antibiotic includes ciprofloxacin and amoxicillin/calvulanic acid with the diameter of inhibition zone 5 and 0 mm respectively. Biogenic chitosan expressed high significant antibiofilm activity with increasing concentration of chitosan NPs. DPPH reducing activity of nanoparticles which increased with increase concentration of biogenic chitosan NPs.

The aim of this study was to study the biomedical activity (antibacterial, antibiofilm, and antioxidant activity) and Characterization of Chitosan NPs synthesized by B. subtilis. Different types of bacterial strains(Z1-Z25) were screened for biosynthesis of chitosan NPs, Isolate (Z2) was selected as efficient isolate based on color change and antibacterial activity against the pathogenic bacteria, and it was diagnosed as Bacillus subtilis, depending on the morphology, microscopic examination and VITEK2 compact system. The characterization of biogenic chitosan NPs was achieved, using: UV visible spectrophotometry was used to describe the synthesis of chitosan NPs by B. subtilis, with an absorption peak at 280nm wavelength. SEM analysis showed the spherical, homogenous with average sizes from 29-51nm. The elemental analyses of biogenic chitosan with EDS showed 33.31% carbon, 10.24 % nitrogen, 50.55% oxygen, 5.34% phosphate and 0.55% chloride. The size and structurer of biogenic chitosan NPs was measured using XRD that appeared at 20°-26°’ AFM analysis showed the average diameter of the biogenic chitosan NPs was 47. 18. The antibacterial activity was studied for biogenic chitosan against pathogenic bacteria (P.aeruginosa, S. aureus, K. pneumonia, E.coli, and P. mirabilis). Biogenic chitosan NPs with deferent concentration (100, 200, 400ug/ml) showed inhibition against all tested bacteria and largest inhibition zone against S. aureus(26mm) with concentration 400 μg/ml. Biogenic chitosan expressed high significant antibiofilm activity with increasing concentration of chitosan NPs. DPPH reducing activity of nanoparticles which increased with increase concentration of biogenic chitosan NPs.