Oxidative stress generation of silver nanoparticles in three bacterial genera and its relationship with the antimicrobial activity

M.A. QUINTEROSA, V. CANO ARISTIZÁBAL, P.R. DALMASSO, M.G. PARAJE, P.L. PÁEZ

TOXICOLOGY IN VITRO : AN INTERNATIONAL JOURNAL PUBLISHED IN ASSOCIATION WITH BIBRA.

PERGAMON-ELSEVIER SCIENCE LTD

Lugar: Amsterdam; Año: 2016 vol. 36 p. 216 - 223

0887-2333

Oxidative stress is a condition caused by the high intracellular concentrations of reactive oxygen species (ROS) that includes superoxide anion radicals, hydroxyl radicals and hydrogen peroxide. Nanoparticles could cause rapid generation of free radicals by redox reactions. ROS can react directly with membrane lipids, proteins and DNA and are normally scavengedbyantioxidantsthatarecapableofneutralizing;however,elevatedconcentrationsofROSinbacterialcellscan resultinoxidativestress.Theaimofthisworkwascontributetotheknowledgeofactionmechanismofsilvernanoparticles(Ag-NPs)andtheirrelationtothegenerationofoxidativestressinbacteria.WedemonstratedthatAg-NPsgenerated oxidative stress in Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa mediated by the increment of ROS and this increase correlated with a better antimicrobial activity. On the other hand, we showed that the oxidative stress caused by the Ag-NPs biosynthesized was associated to a variation in the level of reactive nitrogen intermediates (RNI). Oxidative stress in bacteria can result from disruption of the electronic transport chain due to the high affinity of Ag-NPsforthecellmembrane.Thisimbalanceintheoxidativestresswasevidentiatedbyamacromolecularoxidationat levelofDNA,lipidsand