Biosynthesized silver nanoparticles: decoding their mechanism of action in Staphylococcus aureus and Escherichia coli

QUINTEROS, MELISA A; CANO, ARISTIZABALVIVIANA; ONNAINTY, RENNÉ; MARY, VERÓNICA S; THEUMER MARTÍN, G; GRANERO, GLADYS E.; PARAJE, MARÍA G; PÁEZ, PAULINA L

INTERNATIONAL JOURNAL OF BIOCHEMISTRY AND CELLULAR BIOLOGY

PERGAMON-ELSEVIER SCIENCE LTD

Año: 2018

1357-2725

The oxidative stress generation in bacteria by the presence of antibiotics (in this casesilver nanoparticles (AgNPs)) is already widely known. Previously, we demonstrated thatAgNPs generate oxidative stress in Staphylococcus aureus and Escherichia coli mediated bythe increase of reactive oxygen species (ROS). In this work we are demonstrating theconsequences of the oxidative stress by the presence of AgNPs; these bacterial strainsincreased the levels of oxidized proteins and lipids. In addition, it was possible to determine which reactive oxygen species are mainly responsible for the oxidative damage tomacromolecules. Also, we found that the bacterial DNA was fragmented and the membranepotential was modified. This increase in the levels of ROS found in both, S. aureus and E.coli, was associated with the oxidation of different types of important macromolecules forthe normal functioning of cell, so the oxidative stress would be one of the mechanisms bywhich the AgNPs would exert their toxicity in both strains, one Gram positive and the otherGram negative of great clinical relevance.