Synthesis and effect of silver nanoparticles on the antibacterial activity of different antibiotics against Staphylococcus aureus and Escherichia coli

Ipomea carnea-based silver nanoparticle synthesis for antibacterial activity against selected human pathogens

“…In this study, the average particle size was about 50 nm, and we observed an enhanced antibacterial activity even at a higher number of bacterial colonies (10 7 CFU) at a much lesser nanoparticle concentration (7 mg per disc). Thus, the effective inhibition observed in our studies is in agreement with earlier reports [25,26]. …”

“…Klebsiella pneumoniae and P. vulgaris showed a ZOI of 15 mm (Figure 10). When silver nanoparticles with an average size of 22.5 nm prepared by bacterial reduction were employed, Escherichia coli showed an inhibition zone of around 9 mm (10 mg nanoparticle per disc) [25]. In a different antimicrobial study using chemically synthesised, uncapped silver nanoparticles of 3 nm average size, a ZOI of around 14-15 mm was reported for E. coli strains [26].…”

Antimicrobial properties of nano-silver: A cautionary approach to ionic interference

“…Heating and stirring were continued for 30 min until a clear yellow liquid (silver nanoparticle solution) was observed in the flask. The nanoparticle presence was confirmed using a Perkin Elmer Lambda 900 UV/VIS/NIR Spectrometer to indentify the silver plasmon as discussed in previous studies [7,26]. These in-house synthesised and commercial nanoparticles were then characterised using multiple techniques detailed below to estimate particle size.…”

“…In order to carry out this assay with nanoparticles as opposed to traditional antibiotics the method was adapted slightly Shahaverdi et al [26] have previously outlined a disk diffusion method suitable for the determination of the antimicrobial activity of nanoparticles [26]. A modified version of this method was performed here.…”

“…Nevertheless there has been a significant upsurge in reports of nanomaterials exhibiting antimicrobial properties [25,21,1,15,9]. A deeper investigation reveals that many of these reports merely append a simplistic disk diffusion assay or a variation of this assay to essentially a material synthesis report [26,10]. Often such studies fail to take account of the physicochemical properties of the nanoparticle which have been crucially important in helping to standardise approaches for the assessment of nanoparticle toxicity and are likewise expected to contribute significantly to understanding the antimicrobial properties of nanomaterials [19,28].…”