The Rχ-02 program is focused on engineering novel macrolides that overcome known bacterial resistance modifications. Macrolides are a class of antibiotics that traditionally have shown excellent safety profiles and, until resistance emerged against many macrolides, they were a very effective class of antibiotics. Leveraging our proprietary crystallographic structures of the ribosome has allowed us to identify the atomic locations of these resistance modifications and to produced multiple series of structurally distinct compounds effective against a wide range of pathogens, including those generally associated with nosocomial Gram-positive infections, community respiratory-tract infections and uncomplicated skin and soft tissue infections (uSSTIs) seen both in hospital and community settings.