Synergistic Antibacterial Effect of Silver Nanoparticles Combined with Ineffective Antibiotics on Drug ResistantSalmonella typhimuriumDT104

Abstract

Synergistic antibacterial activity of combined silver nanoparticles (AgNPs) with tetracycline (polykeptide), neomycin (aminoglycoside), and penicillin (β-lactam) was tested against the multidrug resistant bacterium Salmonella typhimurium DT104. Dose-dependent inhibition of Salmonella typhimurium DT104 growth is observed for tetracycline-AgNPs and neomycin-AgNPs combination with IC50 of 0.07 μg/mL and 0.43 μg/mL, respectively. There is no inhibition by the penicillin-AgNPs combination. These results suggest that the combination of the ineffective tetracycline or neomycin with AgNPs effectively inhibits the growth of this bacterium. The synergistic antibacterial effect is likely due to enhanced bacterial binding by AgNPs assisted by tetracycline or neomycin, but not by penicillin.

Silver nanoparticles functionalized with ampicillin

“…It is well known that silver nanoparticles and antibiotics exhibit a synergistic effect . It was also proved that only the simultaneous application of silver nanoparticles and antibiotics gives a positive effect .…”

Mechanistic Study of the Synergistic Antibacterial Activity of Combined Silver Nanoparticles and Common Antibiotics

“…The Salmonella (1 × 10 5 CFU/mL) in PBS was treated with a desired concentration of AgNPs, AgNO 3 , an individual antibiotic, or the combination of the antibiotic with AgNPs for 2 h. Then, 100 μ L of the treated bacterial solution was taken to be plated, followed by incubation for 24 h and colony counting as described before. 24 As a control, tetracycline was chosen as a representative to confirm whether Ag + has a synergistic antibacterial effect when combined with antibiotics. Combinations of 5 μ M Ag + with 0, 0.5, 2, 8, and 16 μ M of tetracycline were tested for inhibition of the 1 × 10 5 CFU/mL bacteria cells.…”

“…24 We hypothesize that the synergistic antibacterial activity correlates with the complex formation between AgNPs and the antibiotic. Since Ag + is a known antibacterial, 25,26 the release of Ag + from AgNPs into solution was also examined under various experimental conditions.…”

Green synthesis of silver chloride nanoparticles using Prunus persica L. outer peel extract and investigation of antibacterial, anticandidal, antioxidant potential

“…These data clearly demonstrated that antibacterial activity increased by mixing the prescribed antibiotics such as kanamycin or rifampicin with PE-AgClNPs. It is seen that at lower concentrations, the AgNPs are not effective, however when they were mixed with the standard antibiotics, their activity increased, the possible reason behind this activity might be due to the enhanced bacterial binding by AgNPs assisted by the standard antibiotics, kanamycin and rifampicin (56). A more probable cause of the synergistic effect may be the potential use of the AgNPs as the drug carrier.…”