KETOLIDES (TELITHROMYCIN)

Ketolides and macrolides have very similar antibacterial properties
Ketolides and macrolides have the same ribosomal target site
The principal difference between the two is that structural modifications within ketolides neutralize the common resistance mechanisms that make macrolides ineffective
Introduction of the 3-keto function converts a methylase-inducing macrolide into a noninducing ketolide
This moiety also prevents drug efflux, probably because it generates a less-desirable substrate