Silver Nanoparticles: Biosynthesis Using an ATCC Reference Strain of Pseudomonas aeruginosa and Activity as Broad Spectrum Clinical Antibacterial Agents

Abstract EN

Currently, the biosynthesis of silver-based nanomaterials attracts enormous attention owing to the documented antimicrobial properties of these ones.

This study reports the extracellular biosynthesis of silver nanoparticles (Ag-NPs) using a Pseudomonas aeruginosa strain from a reference culture collection.

A greenish culture supernatant of P.

aeruginosa incubated at 37°C with a silver nitrate solution for 24 h changed to a yellowish brown color, indicating the formation of Ag-NPs, which was confirmed by UV-vis spectroscopy, transmission electron microscopy, and X-ray diffraction.

TEM analysis showed spherical and pseudospherical nanoparticles with a distributed size mainly between 25 and 45 nm, and the XRD pattern revealed the crystalline nature of Ag-NPs.

Also it provides an evaluation of the antimicrobial activity of the biosynthesized Ag-NPs against human pathogenic and opportunistic microorganisms, namely, Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecalis, Proteus mirabilis, Acinetobacter baumannii, Escherichia coli, P.

aeruginosa, and Klebsiella pneumonia.

Ag-NPs were found to be bioactive at picomolar concentration levels showing bactericidal effects against both Gram-positive and Gram-negative bacterial strains.

This work demonstrates the first helpful use of biosynthesized Ag-NPs as broad spectrum bactericidal agents for clinical strains of pathogenic multidrug-resistant bacteria such as methicillin-resistant S.

aureus, A.

baumannii, and E.

coli.

In addition, these Ag-NPs showed negligible cytotoxic effect in human neutrophils suggesting low toxicity to the host.