Impact of Natural Synthesized Silver Nanoparticles on Soft Tissue Infecting Bacteria

Abstract

This study includes the impact of some natural synthesized silver nanoparticles on soft tissue infecting bacteria (Staphylococcus aureus, Pseudomonas aeruginosa, E. coli, and Klebsiella pneumoniae). This study represents a simple, reliable, cost effective and green method for the synthesis of Ag NPs by treating silver ions with different concentrations of peel extract of Citrus paradisi, (1-Ag NPs, 2-Ag NPs, and 3-Ag NPs). Synthesized silver nano formulations were characterized by ultraviolet-visible absorption spectroscopy, dynamic light scattering (DLS), zeta potential and transmission electron microscopy (TEM). The antibacterial activity of Ag NPs was evaluated using a series of assays: well diffusion method, disc diffusion method, antibiotic susceptibility test, and microdilution method. The mean particle size of prepared silver nanoparticles are 19.76 nm, 16.99 nm and 5.89 nm for 1-Ag NPs, 2-Ag NPs, and 3-Ag NPs, respectively. The prepared silver nanoparticles inhibited all the tested organisms. The smallest nanoparticle size had the greatest inhibitory effect concerning to the other antimicrobial agent (antibiotics Polimixin B (PB) (300unit), Ciprofloxacin CIP (5μg), Tigecyclin TGC (15μg), Aztreonam AT(30μg), Cefepime FEP (30μg), Cefoxitin CX (30μg), Ceftriaxone CTR (30μg), Amoxicillin/Clavulanic acid AMC (30μg), Ceftazidime CAZ (30μg), Piperacillin/Tazobactam PIT (100/10μg), Imipenem IPM (10μg), Meropenem MRP (10μg), Amikacin AK (30μg), Co-Trimoxazole (Sulpha/Trimethoprim) COT (25μg), Ampicillin AMP (10μg), Gentamicin GEN (10μg), Ofloxacin OF (5μg), Levofloxacin LEV (5μg), Doxycycline Hydrochloride DO (30μg), Erythromycin E (15μg), Clindamycin CD (2μg), Vancomycin VA (30μg), Ampicillin/Sulbactam A/S (10/10 μg), Azithromycin AZM (15μg), Linezolid LZ (30μg), Cefaclor CF (30μg), Teicoplanin TEC (30μg), Cefuroxime CXM (30μg)). Some of tested bacteria (Staphylococcus aureus, Pseudomonas aeruginosa, and E. coli) were moderately sensitive except Klebsiella pneumoniae which was completely resistant. This point that the use of silver nanoparticles Ag NPs was the best favorable for control of Klebsiella pneumoniae. Concerning microdilution method, the result indicated the Klebsiella pneumoniae was the most inhibited bacteria with MIC concentration 0.047μg/mL and Pseudomonas aeruginosa the least inhibited bacteria with MIC concentration 0.19 μg/mL. Concerning transmission electron microscope TEM, the result indicated the tested bacteria (Staphylococcus aureus, Pseudomonas aeruginosa) showed wall  rupture and extrusion of the cellular contents as consequence of adhesion of nanoparticles upon bacterial cell surface. These results suggest that Ag NPs could be used as an adjuvant for the treatment of soft tissue infection.