Recent developments on ketolides and macrolides.

Recent semi-synthetic studies of erythromycin A culminated in the discovery of two ketolide drug candidates, HMR-3647 and ABT-773, for the treatment of community-acquired bacterial infections caused by both macrolide- and beta-lactam-susceptible and -resistant S. pneumoniae, gram negative bacteria, and intracellular atypical pathogens. The discovery of ketolides has rekindled interest in macrolides, and recent efforts have also led to a novel class of 4''-carbamates with activity against macrolide-resistant organisms. This review is an account of recent developments on ketolides and macrolides in terms of both chemistry and antibacterial activity.