Ketolides are a new generation of macrolide antibiotics designed to overcome issues with bacterial resistance to macrolides. They are semi-synthetic antibiotics derived from erythromycin (macrolide antibiotic) and the changes give ketolides a broader spectrum of activity.
Ketolides bind to the bacterial 50S ribosomal subunit and inhibit RNA-dependent protein synthesis. They are bacteriostatic at low concentrations and bactericidal at high concentration, so basically exhibit concentration dependent killing.
Ketolides have good antibacterial activity against Gram-positive bacteria such as those that cause respiratory tract infections.
