Electrochemically Synthesized Silver Nanoparticles Are Active Against Planktonic and Biofilm Cells of Pseudomonas aeruginosa and Other Cystic Fibrosis-Associated Bacterial Pathogens

Abstract

A novel, electrochemically synthesized, silver nanoparticles (AgNPs) formulation was evaluated in vitro against Pseudomonas aeruginosa, Burkholderia cepacia, Stenotrophomonas maltophilia, and Staphylococcus aureus strains from cystic fibrosis (CF) patients. AgNPs were particularly active against P. aeruginosa and B. cepacia planktonic cells (median MIC: 1.06 and 2.12 μg/ml, respectively) by a rapid, bactericidal and concentration-dependent effect. AgNPs showed to be particularly effective against P. aeruginosa and S. aureus biofilm causing a viability reduction ranging from 50% (1×MIC) to >99.9% (4×MIC). Electron microscopy showed that AgNPs deconstruct extracellular matrix of P. aeruginosa biofilm, and accumulate at the cell surface causing cell death secondary to membrane damage. Compared to Tobramycin, AgNPs showed comparable, or even better, activity against planktonic and biofilm P. aeruginosa cells. AgNPs at concentrations effective against B. cepacia and P. aeruginosa were not toxic to G. mellonella larvae. Our silver-based formulation might be an alternative to antibiotics in CF patients. Further in vitro and in vivo studies are warranted to confirm this therapeutic potential.

Genomic and phenotypic characterization of Burkholderia isolates from the potable water system of the International Space Station

“…Alternatives to iodine have been considered for future PWD microbial disinfection, such as the use of silver in the form of silver (I) fluoride [3,39]. The effect of silver treatment upon B. cepacia has been explored as a clinical alternative to antibiotics [40] and will likely reduce this microbial load. However, we find that the ISS B. cepacia isolates analyzed in this study all harbored a Cu/Ag efflux pump (CusA) at a mean copy number of 3.05 ± 3.4 on a conjugative plasmid ( Table 5).…”

Genomic and phenotypic characterization ofBurkholderiaisolates from the potable water system of the International Space Station

“…Alternatives to iodine have been considered for future PWD microbial disinfection, such as the use of silver in the form of silver (I) fluoride [3,32]. The effect of silver treatment upon B. cepacia has been explored as a clinical alternative to antibiotics [33] and will likely reduce this microbial load. However, we find that the ISS B. cepacia isolates analyzed in this study all harbored a Cu/Ag efflux pump (CusA) at a mean copy number of 3.05 ± 3.4 on a conjugative plasmid (Table 4).…”

Novel Therapeutic Strategies Applied to Pseudomonas aeruginosa Infections in Cystic Fibrosis

“…Both organic and inorganic nanoparticles proved intrinsic antimicrobial properties and they are widely utilized as vectors for the delivery of natural and synthetic antimicrobials [15]. Inorganic NPs, such as silver NPs proved their antimicrobial efficiency against CF recovered multidrug resistant pathogens, such as P. aeruginosa, Burkholderia cepacia, Stenotrophomonas maltophilia, and S. aureus strains [16]. Silver NPs (AgNPs) proved highly bactericidal effect on the drug-resistant or multidrug-resistant P. aeruginosa with the minimum inhibitory concentration (MIC) range of 1.406-5.625 µg/mL and the minimum bactericidal concentration (MBC) range of 2.813-5.625 µg/mL.…”