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Showing 2 results for Honarmand Jahromi
Volume 9, Issue 1 (Winter 2023)
Abstract
Backgrounds: This study was conducted with the aim of isolation and molecular identification of Streptomyces spp. producing antibacterial compounds from Iranian soil.
Materials & Methods: In this study, 50 soil samples were collected from different areas of Sanandaj city. Soil samples were cultured on starch casein media. Streptomyces species were characterized using morphological and biochemical assays. Molecular identification was performed by 16S rRNA sequencing. Antimicrobial activity was evaluated using perpendicular streak and agar well diffusion methods.
Findings: To identify active Streptomyces strains in terms of producing antibacterial agents, screening was performed in two stages. Among 20 Streptomyces strains isolated from soil samples, six isolates were selected in the primary screening stage based on their ability to limit the growth of pathogens. Of the two solvents used in the secondary screening stage, ethyl acetate was the most suitable solvent for extracting effective metabolites of Streptomyces. Among the six isolates selected based on their antimicrobial activity, two isolates with the highest antibacterial activity were selected for the sequencing process. By analyzing the dendrogram and the data obtained from the NCBI database, it was found that one isolate (Yellow 4A) was 98% similar to S. fradiae, and the other isolate (Green 4A) was 98% similar to S. coelicolor.
Conclusion: The use of proper strategies to identify potential new Streptomyces species with antibacterial properties may bring a bright future in the treatment of resistant pathogens. However, more studies are required to detect active metabolites of the mentioned isolates.
Volume 24, Issue 3 (Fall 2021)
Abstract
Treatment of infections caused by multidrug-resistant bacteria has become a global challenge. The combined therapies involve the simultaneous use of two or more biological agents with different mechanisms of action, which are more effective than traditional treatments for diseases that act only in one way. The aim of this study was synergistic antibacterial activity of synthesized graphene oxide/chitosan (GO/CS) nanocomposite with Rosmarinus officinalis L. essential oil against multidrug-resistant (MDR) bacteria. R. officinalis essential oil was extracted and its chemical compounds were analyzed by gas chromatography and mass spectrometry. The GO/CS nanocomposite was synthesized. The size and structure of the synthesized nanoparticles were evaluated by EDS, XRD, FE-SEM, and FTIR analysis. Antibacterial activity of chitosan, graphene oxide, GO/CS nanocomposite and R. officinalis essential oil was studied by broth microdilution method against 5 MDR isolates of A. baumannii, P. aeruginosa and E. coli. The antimicrobial interaction of the essential oil and GO/CS composite was studied by checkerboard titration method. The results showed that chitosan, graphene oxide and GO/CS had no antimicrobial activity in the studied concentrations. The MIC of R. officinalis essential oil was obtained between 0.12-256 μl/ml. R. officinalis essential oil in combination with GO/CS nanocomposite had a synergistic effect against 5 isolates of P. aeruginosa and 2 isolates of A. baumannii, and caused an additive effect against two isolates of E. coli. Based on the findings of this study, this combination can be effective against some MDR isolates and could be used to treat infections caused by these isolates.
