Azithromycin (ophthalmic) microbiology
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Sheng Shi, M.D. [2]
Microbiology
Azithromycin acts by binding to the 50S ribosomal subunit of susceptible microorganisms and interfering with microbial protein synthesis.
Azithromycin has been shown to be active against most isolates of the following microorganisms, both in vitro and clinically in conjunctival infections [see Indications and Usage (1)].
- CDC coryneform group G2
- Haemophilus influenzae
- Staphylococcus aureus
- Streptococcus mitis group
- Streptococcus pneumoniae
The following in vitro data are also available, but their clinical significance in ophthalmic infections is unknown. The safety and effectiveness of AzaSite in treating ophthalmological infections due to these microorganisms have not been established.
The following microorganisms are considered susceptible when evaluated using systemic breakpoints. However, a correlation between the in vitro systemic breakpoint and ophthalmological efficacy has not been established. This list of microorganisms is provided as an aid only in assessing the potential treatment of conjunctival infections.
Azithromycin exhibits in vitro minimal inhibitory concentrations (MICs) of equal or less (systemic susceptible breakpoint) against most (≥90%) of isolates of the following ocular pathogens:
- Chlamydia pneumoniae
- Chlamydia trachomatis
- Legionella pneumophila
- Moraxella catarrhalis
- Mycoplasma hominis
- Mycoplasma pneumoniae
- Neisseria gonorrhoeae
- Peptostreptococcus species
- Streptococci (Groups C, F, G)
- Streptococcus pyogenes
- Streptococcus agalactiae
- Ureaplasma urealyticum
- Viridans streptococci
Efficacy for this organism was studied in fewer than 10 infections.[1]
References
Adapted from the FDA Package Insert.