Azithromycin Better Than Clarithromycin for Mycobacterium abscessus Infection

Clarithromycin — but not azithromycin — was associated with significantly increased expression of erm(41), an inducible resistance gene. Azithromycin performed better than clarithromycin in a mouse-infection model.

Mycobacterium abscessus is resistant to many antibiotics in vitro, but the macrolides clarithromycin (CLR) and azithromycin (AZM) retain activity. However, M. abscessus could rapidly develop resistance to macrolides through induction of the ribosomal methyltransferase gene erm(41).

M. abscessus was recently split into a complex that includes M. abscessus and — as a separate species — Mycobacterium massiliense. M. massiliense does not have the erm(41) gene and responds to CLR better than M. abscessus. Researchers recently examined several questions regarding management of infections caused by these two pathogens.

On in vitro testing, all 23 M. abscessus isolates developed a high level of inducible CLR resistance within 14 days. Although they a…

Reviewing Author

Neil M. Ampel, MD

Disclosures

Editorial BoardsUpToDate

Leadership Positions in Professional SocietiesCoccidioidomycosis Study Group (Past President, Secretary, Treasurer)

Neil M. Ampel, MD

Disclosures

Editorial BoardsUpToDate

Leadership Positions in Professional SocietiesCoccidioidomycosis Study Group (Past President, Secretary, Treasurer)