Ketolides are antibiotics belonging to the macrolide group. Ketolides are derived from erythromycin by substituting the cladinose sugar with a keto-group and attaching a cyclic carbamate group in the lactone ring. These modifications give ketolides much broader spectrum than other macrolides. Moreover, ketolides are effective against macrolide-resistant bacteria, due to their ability to bind at two sites at the bacterial ribosome.

The only ketolide on the market at this moment is telithromycin, which is sold under the brand name of Ketek.http://products.sanofi-aventis.us/ketek/ketek.html

Another promising ketolide is cethromycin.

Macrolide antibiotics