Comparison of macromolecular oxidation by reactive oxygen species in three bacterial genera exposed to different antibiotics.

Proteins and lipids maybe important targets of oxidation and this may alter their functions. We evaluated whether ceftazidima (CAZ), piperacillin (PIP), chloramphenicol (CMP), and ciprofloxacin (CIP) could oxidize the macromolecules in the three bacterial genera Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa. There was an increase in lipid peroxidation observed in these three species. However, this was lower in the Gram negative bacteria than in S. aureus. A reduction of the carbonyl residue in S. aureus with ciprofloxacin was observed whereas in Gram negative bacteria the antibiotics increased the carbonyl residue with respect to the control. Although the strains suffered a rise in advanced oxidation protein products (AOPP) in the presence of ciprofloxacin, the S. aureus strain had a smaller increase of AOPP than the other strains. The results described in this article provide data about the susceptibility of the three bacterial genera to the oxidative stress induced by the antibiotics studied.