Azithromycin is an azalide antibiotic, a subclass of macrolide antibiotic. It acts by binding to the 50s ribosomal subunit of susceptible microorganisms and thus interfering with microbial protein synthesis. Azithromycin has been shown to be active against most strains in the following microorganisms, both In vitro and in clinical infections:
Gram-positive microorganisms: Staphylococcus aureus, Streptococcus agalactiae, Streptococcus pneumoniae, Streptococcus pyogenes.
Gram-negative microorganisms: Haemophilus ducreyi, Haemophilus influenzae, Moraxella catarrhalis, Neisseria gonorrhoeae, Escherichia coli.