Synergistic antibacterial activity of silver with antibiotics correlating with the upregulation of the ROS production

Sci Rep. 2018 Jul 24;8(1):11131. doi: 10.1038/s41598-018-29313-w.

Abstract

Thiol-dependent enzymes, including the thioredoxin (Trx) and glutathione (GSH) systems, have recently been found as promising bactericidal targets in multidrug-resistant (MDR) bacteria. We previously discovered that silver acted synergistically with ebselen in the inhibition of the Trx system and also resulted in a fast depletion of GSH in Gram-negative bacteria. Silver has been found by others to improve the sensitivity of bacteria to certain conventional antibiotics. Here, we found that the synergistic antibacterial effects of silver with four conventional antibiotics was correlated with the blockage of bacterial Trx system by silver. The synergistic antibacterial effect came along with the production of reactive oxygen species. All these results suggested that silver primarily enhanced the bactericidal activities of conventional antibiotics towards Gram-negative strains through the upregulation of ROS production.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anti-Bacterial Agents / chemistry
  • Anti-Bacterial Agents / pharmacology*
  • Azoles / pharmacology
  • Drug Resistance, Multiple, Bacterial / drug effects
  • Drug Resistance, Multiple, Bacterial / genetics
  • Escherichia coli / drug effects
  • Escherichia coli / pathogenicity
  • Glutathione / antagonists & inhibitors
  • Glutathione / genetics
  • Gram-Negative Bacteria / drug effects*
  • Gram-Negative Bacteria / enzymology
  • Gram-Negative Bacteria / pathogenicity
  • Humans
  • Metal Nanoparticles / chemistry
  • Microbial Sensitivity Tests
  • Organoselenium Compounds / pharmacology
  • Reactive Oxygen Species / metabolism
  • Silver / pharmacology*
  • Thioredoxins / antagonists & inhibitors*
  • Thioredoxins / genetics

Substances

  • Anti-Bacterial Agents
  • Azoles
  • Organoselenium Compounds
  • Reactive Oxygen Species
  • Silver
  • ebselen
  • Thioredoxins
  • Glutathione