<p>Synergistic ROS-Associated Antimicrobial Activity of Silver Nanoparticles and Gentamicin Against <em>Staphylococcus epidermidis</em></p>

Abstract

Introduction: Increasing bacteria resistance to antibiotics is a major problem of healthcare system. There is a need for solutions that broaden the spectrum of bactericidal agents improving the efficacy of commonly used antibiotics. One of the promising directions of search are silver nanoparticles (obtained by different methods and displaying diversified physical and chemical properties), and their combination with antibiotics. Purpose: In this study, we tested the role of reactive oxygen species in the mechanism of synergistic antibacterial activity of gentamicin and Tween-stabilized silver nanoparticles against gentamicin-resistant clinical strains of Staphylococcus epidermidis. Methods: Synergistic bactericidal activity of gentamicin and silver nanoparticles stabilized with non-ionic detergent (Tween 80) was tested by the checkerboard titration method on microtiter plates. Detection of reactive oxygen species was based on the chemiluminescence of luminol. Results: Hydrophilic non-ionic surface functionalization of silver nanoparticles enabled the existence of non-aggregated active nanoparticles in a complex bacterial culture medium. Tween-stabilized silver nanoparticles in combination with gentamicin exhibited bactericidal activity against multidrug-resistant biofilm forming clinical strains of Staphylococcus epidermidis. A synergistic effect significantly decreased the minimal inhibitory concentration of gentamicin (the antibiotic with numerous undesirable effects). Gentamicin significantly enhanced the generation of reactive oxygen species by silver nanoparticles. Conclusion: Generation of reactive oxygen species by Tween-coated metallic silver nanoparticles was significantly enhanced by gentamicin, confirming the hypothesis of oxidative-associated mechanism of the synergistic antibacterial effect of the gentamicin-silver nanoparticles complex.

<p>Synergistic Nanocomposites of Different Antibiotics Coupled with Green Synthesized Chitosan-Based Silver Nanoparticles: Characterization, Antibacterial, in vivo Toxicological and Biodistribution Studies</p>

“…The mechanism of synergistic activity of CS-AgNPs in combination with different antibiotics was evaluated by the assessment of hydroxyl radical generation using the luminol chemiluminescence method. 31 The production of hydroxyl radicals was evaluated by mixing 100 µL of luminol solution with 100 µL AgNPs and 2 µL of antibiotic water solution (40 mg/mL) to obtain a final concentration of 0.4 mg/mL for each antibiotic while combinations of these agents were used at their FICs.…”

“…54 In addition, chemical interaction as the possible cause of the synergistic rise in antibacterial activity of the synthesized AgNPs with antibiotic. 31,58 However, it was also postulated that the combined effect of antimicrobials drives synergy by membrane alterations generated by AgNPs, and no chemical interactions were detected between AgNPs and antibiotics. 59 Moreover, it was also reported that amino and hydroxyl groups present in tested…”

The Combined Use of Gentamicin and Silver Nitrate in Bone Cement for a Synergistic and Extended Antibiotic Action against Gram-Positive and Gram-Negative Bacteria

“…However, when gentamicin was used at concentrations that had no effect on the growth of either S. aureus or P. aeruginosa the addition of silver nitrate almost fully inhibited bacterial growth at concentrations of just 0.4 µg/mL or 0.03 µg/mL, respectively ( Figure 2 and Figure 3 ). Clearly these combined effective concentrations point to a powerful synergistic activity, a phenomenon that has previously been reported for gentamicin and other antibiotics [ 34 , 37 , 38 , 39 , 40 , 41 , 42 ]. Interestingly, the data might suggest an alternative selection of silver over gentamicin as a single agent for inclusion in bone cement.…”

Assessing the potential biological activities of TiO2 and Cu, Ni and Cr doped TiO2 nanoparticles

“…[1][2][3][4] Nanoparticles exert their antimicrobial action by binding to the surface of microbial cell membranes and altering their basic cellular functions. 5 Moreover, nanoparticles have been reported to penetrate the microbial cells and interact with nitrogen, sulfur and phosphorus of biomolecules. 6 The size and morphology of nanoparticles have been found to exhibit noticeable potential for certain biological activities.…”