Biosynthesized silver nanoparticles: decoding their mechanism of action in S. aureus and E. coli.

MELISA DE LOS ANGELES QUINTEROS; VIVIANA CANO ARISTIZÁBAL; MARIA GABRIELA PARAJE; PAULINA L PÁEZ

Paris

Congreso; 9th Euro-Global Summit on Toxicology and Applied Pharmacology.; 2017

The generation of oxidative stress in bacteria by the presence of silver nanoparticles (AgNPs) is already widely known1,2. If the cell cannot respond to oxidative injury produced by increased species reactive oxygen (ROS),the oxidation of macromolecules such as proteins, lipids and DNA occurs, leading to the death of the bacterium3,4. In previous results (Quinteros et al.5), we observed as biosynthesized AgNPs that had antibacterial activity, generated an increase of ROS and RNI in Staphylococcus aureus, Escherichia coliand Pseudomonas aeruginosa, being responsible for their toxicity and bacterialdeath. According to the above, we set out to delve into the mechanism of action of AgNPs, by determining markers of oxidative stress, such as protein oxidation, lipids, DNA and changes in membrane potential in two reference strains S. aureus ATCC 29213 and E. coli ATCC 25922. We found that the increase in the levels of ROS is associated with the oxidation of different macromolecules important for the normal functioning of the cell, so that oxidative stress would be one of themechanisms by which the AgNPs would exert their toxicity in these two strains of great clinical relevance. In this way, we are making a great contribution on the toxicity produced by AgNPs.