Silver nanoparticles produced from Cedecea sp. exhibit antibiofilm activity and remarkable stability

Abstract

With multidrug-resistant bacterial pathogens on the rise, there is a strong research focus on alternative antibacterial treatments that could replace or complement classical antibiotics. Metallic nanoparticles, and in particular silver nanoparticles (AgNPs), have been shown to kill bacterial biofilms effectively, but their chemical synthesis often involves environmentally unfriendly by-products. Recent studies have shown that microbial and plant extracts can be used for the environmentally friendly synthesis of AgNPs. Herein we report a procedure for producing AgNPs using a putative Cedecea sp. strain isolated from soil. The isolated bacterial strain showed a remarkable potential for producing spherical, crystalline and stable AgNPs characterized by UV–visible spectroscopy, transmission electron microscopy, dynamic light scattering, and Fourier transform infrared spectroscopy. The concentration of produced nanoparticles was 1.31 µg/µl with a negative surface charge of − 15.3 mV and nanoparticles size ranging from 10–40 nm. The AgNPs was tested against four pathogenic microorganisms S. epidermidis, S. aureus, E. coli and P. aeruginosa. The nanoparticles exhibited strong minimum inhibitory concentration (MIC) values of 12.5 and 6.25 µg/µl and minimum bactericidal concentration (MBC) values of 12.5 and 12.5 µg/mL against E. coli and P. aeruginosa, respectively. One distinguishing feature of AgNPs produced by Cedecea sp. extracts is their extreme stability. Inductively coupled plasma mass spectrometry and thermogravimetric analysis demonstrated that the produced AgNPs are stable for periods exceeding one year. This means that their strong antibacterial effects, demonstrated against E. coli and P. aeruginosa biofilms, can be expected to persist during extended periods.

Biosynthesis, Characterization and Antibacterial Application of Novel Silver Nanoparticles against Drug Resistant Pathogenic Klebsiella pneumoniae and Salmonella Enteritidis

“…FT-IR spectrum of bacterial culture supernatant also displayed the identical vibrational stretches at 3256.21, 2931.72, 2877.00, 2021.83, 1997.98, 1592.94, 1452.79, 1395.89 and 1040.80 cm −1 ( Figure 4 B). The results of this study coincided with other reports [ 23 , 27 , 38 ]. FT-IR analysis revealed the binding of carbohydrates, proteins, and phospholipids with synthesized NPs which contributed for the stability of NPs, as well as capping and functionalizing agents.…”

“…A similar particle size was formed by Cedecea sp. in the range of 10–40 nm [ 38 ]. Energy dispersive X-Ray (EDX) and elementary mapping was used to investigate the purity and elemental composition of synthesized AgNPs.…”

“…NPs have a high surface–volume ratio with a small size that makes them capable to interact with microbial surfaces. The large surface area of AgNPs promotes their interaction with pathogens to perform antimicrobial activities [ 38 ]. In the present study, the inhibitory potential of Massilia sp.…”

“…MAHUQ-52 mediated synthesized AgNPs against K. pneumoniae and S. Enteritidis was significantly higher than the tested antibiotics. The inhibitory action of AgNPs against pathogens due to their small size and large surface area make it perfect to interact with the microbial cell membrane [ 38 ]. Massilia sp.…”

Characterization and Genome Analysis of Arthrobacter bangladeshi sp. nov., Applied for the Green Synthesis of Silver Nanoparticles and Their Antibacterial Efficacy against Drug-Resistant Human Pathogens

“…Singh et al reported a similar particle size (10-40 nm) of AgNPs that was synthesized by Cedecea sp. [43]. The elemental composition and purity of synthesized AgNPs was examined by EDX, as shown in Figure 5.…”