Endogenous Nitric Oxide Protects Bacteria Against a Wide Spectrum of Antibiotics

It's a Gas Many antibiotics, including beta-lactams, aminoglycosides, and quinolones, kill bacteria (at least in part) by oxidative stress. Gusarov et al. (p. 1380 ) show that nitric oxide (NO) produced by bacterial NO synthases (bNOS) protects bacteria, including Staphylococcus aureus and Bacillus anthracis , against toxic agents they may encounter in the soil or in host organisms. Thus, bNOS activity is specifically induced in response to antibiotics and, in turn, activates the expression of another key antioxidant enzyme: superoxide dismutase. Hence, NO-mediated antibiotic resistance not only operates by direct chemical modification of toxic molecules, but also alleviates oxidative stress caused by naturally occurring antibiotics.