Macrolide antibiotics, 16-membered antimicrobial spectrum

Macrolides with 14- and 16-membered rings have been productive sources of semisynthetic derivatives that have significantly extended the utility of the mac-rolide class as important antibiotics. New semisynthetic derivatives have exhibited a variety of improved features, such as an expanded antimicrobial spectrum, increased potency, greater efficacy, better oral bioavailability, extended chemical... 

Most of the data on rokitamycin have been published in Japanese and Italian journals. As a propionyl ester of leucomycin, rokitamycin has an antimicrobial spectrum similar to that of erythromycin, it is especially potent against L. pneumophila, M. pneumoniae, and Chlamydia. Like other 16-membered macrolides, it is active against bacteria that are inducibly resistant to erythromycin but inactive against strains that are constitutively resistant to macrolide-lincosamide-streptogramin B antibiotics. 

Oleandoniycin. C35H ,NO,2, Mr 687.87, mp. 110°C, [a][> -65° (CH3OH). Internationa free name for a 14-membered macrolide antibiotic with a broad spectrum of antimicrobial activity isolated from cultures of Streptomyces antibioticus. O. is readily soluble in methanol, ethanol, butanol, acetone, less soluble in wa-... 

Oleandomycin, a 14-membered ring macrolide antibiotic, was isolated in 1956 from fermentation broths of Streptomyces antibioticus [360]. Some years later, oleandomycin was assigned the structure 340 on the basis of its chemical degradation [361]. Oleandomycin is effective, but less potently, against the same spectrum of bacteria as erythromycin, namely Gram-positive bacteria such as staphylococci, streptococci, and pneumococci. The antimicrobial activity of oleandomycin, when combined with tetracycline, is potentiated. In fact, in such a combination it is sold as an antibacterial agent for upper and lower respiratory tract infection. 

Erythromycin, from the actinomycete Saccharo-polyspora (formerly Streptomyces) erythraea, is the first member of this family of antibiotics to be marketed and successfully used clinically to treat infections in humans. It has an antimicrobial spectrum at least as wide as the penicillins, and interestingly, from our perspective, it is often used as a replacement for patients allergic to that group of drags. Besides erythromycin, other members of the macrolide family of antibiotics that are clinically useful include azithromycin, clarithromycin, dirithromycin, roxithromycin, telithromycin (these six are approved by the FDA), oleandomycin, and spiramycin. Clarithromycin, dirithromycin, and roxithromycin and the azalide azithromycin are more recent members of the group and can be regarded as newer generation macrolide antibiotics. 

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