Green Extracellular Synthesis of Silver Nanoparticles by Pseudomonas alloputida, Their Growth and Biofilm-Formation Inhibitory Activities and Synergic Behavior with Three Classical Antibiotics

Abstract

Bacterial resistance to antibiotics is on the rise and hinders the fight against bacterial infections, which are expected to cause millions of deaths by 2050. New antibiotics are difficult to find, so alternatives are needed. One could be metal-based drugs, such as silver nanoparticles (AgNPs). In general, chemical methods for AgNPs’ production are potentially toxic, and the physical ones expensive, while green approaches are not. In this paper, we present the green synthesis of AgNPs using two Pseudomonas alloputida B003 UAM culture broths, sampled from their exponential and stationary growth phases. AgNPs were physicochemically characterized by transmission electron microscopy (TEM), total reflection X-ray fluorescence (TXRF), infrared spectroscopy (FTIR), dynamic light scattering (DLS), and X-ray diffraction (XRD), showing differential characteristics depending on the synthesis method used. Antibacterial activity was tested in three assays, and we compared the growth and biofilm-formation inhibition of six test bacteria: Bacillus subtilis, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus aureus, and Staphylococcus epidermidis. We also monitored nanoparticles’ synergic behavior through the growth inhibition of E. coli and S. aureus by three classical antibiotics: ampicillin, nalidixic acid, and streptomycin. The results indicate that very good AgNP activity was obtained with particularly low MICs for the three tested strains of P. aeruginosa. A good synergistic effect on streptomycin activity was observed for all the nanoparticles. For ampicillin, a synergic effect was detected only against S. aureus. ROS production was found to be related to the AgNPs’ antibacterial activity.

Antimicrobial, Antibiofilm and Antiurease Activities of Microbially Synthesized Silver Nanoparticles against Proteus mirabilis

“…Antibiofilm properties of AgNPs synthesized by Pseudomonas alloputida have been reported against Bacillus subtilis, E. coli, Klebsiella pneumoniae, P. aeruginosa, S. aureus, and S. epidermidis pathogens (Pernas-Pleite et al, 2022). This result showed that infections due to biofilms can be prevented and treated with AgNPs.…”

“…Microorganisms have been used frequently in the biosynthesis of NPs in recent years and Pseudomonas species is one of the most preferred microorganisms in this regard and have been used in biosynthesis of various particles such as AgNPs (John et al, 2020;Yang et al, 2020;Pernas-Pleite et al, 2022), AuNPs (Husseiny et al, 2007) and ZnO-NPs (Abdo et al, 2021). The UV-visible spectrum of the synthesized AgNPs was determined by a spectrophotometer (Figure 1).…”

Extracellular biosynthesis of silver nanoparticles using cell suspension ofRhodococcus fascians

“…Among different sources of nano particles, bacteria hold more interest due to their lower cost, rapid procedure and faster reproduction rates than fungi or plants [23,24]. Bacteria offer numerious examples for biosynthesis of AgNPs , such as Pseudomonas alloputida [25], Bacillus cereus [26], B. pumilus [27],…”

“…Among different sources of nano particles, bacteria hold more interest due to their lower cost, rapid procedure and faster reproduction rates than fungi or plants [23,24]. Bacteria offer numerious examples for biosynthesis of AgNPs, such as Pseudomonas alloputida [25], Bacillus cereus [26], B. pumilus [27], B. subtillus and B. megaterium [28], Pseudomonas spp [29], and Terrabacter humi [30], and Oscillatoria limnetica [31]. In this study, we developed a biological method for synthesizing AgNPs using Rhodococcus fascians .…”

Carboxymethyl Cellulose/Gelatin Hydrogel Films Loaded with Zinc Oxide Nanoparticles for Sustainable Food Packaging Applications

“…They are being used as new modes of food coatings. Encapsulation of biopolymers matrices, and food packaging materials for functional foods, proteins and polysaccharides have gained a lot of attention recently [ 1 , 2 , 3 ]. Active packaging is thought to be the best way to increase the safety and shelf life of food [ 4 ].…”