Erythromycin

Erythromycin is a macrolide antibiotic which is used when the patient has an allergy to penicillins, for it has an antimicrobial spectrum similar to penicillin. It used in the treatment of respiratory tract infections, and has better coverage of atypical organisms, including mycoplasma and Legionellosis. It is no longer recommended by the American Heart Association and the American Dental Association for treatment of bacterial endocarditis in patients hypersensitive to penicillin.

Erythromycin is a macrocyclic compound which contains a 14-membered lactone ring with ten asymmetric centers and two sugars (L-cladinose and D-desoamine), which makes it very difficult to produce via synthetic methods. Erythromycin is produced from a strain of the actinomycete Saccharopolyspora erythraea, formerly known as Streptomyces erythraeus. It is administered orally under the brand name of Eryc.