Comparison of azithromycin and moxifloxacin against bacterial isolates causing conjunctivitis

Christina Ohnsman, David Ritterband, Terrence O'Brien, Dalia Girgis, Al Kabat

Research output: Contribution to journalArticlepeer-review

22 Scopus citations


Objective: To examine in vitro resistance to azithromycin and moxifloxacin in bacterial conjunctivitis isolates. Methods: MIC90s (Minimum Inhibitory Concentration) and resistance rates to azithromycin and moxifloxacin were determined based upon microtiter broth dilution and/or antimicrobial gradient test strips in a multicenter phase III study and confirmed externally. Results: The most common isolates collected from bacterial conjunctivitis patients in the phase III study were Haemophilus influenzae (40.6%), followed by Staphylococcus epidermidis (19.3 %), Propionibacterium acnes (17.3%), Streptococcus pneumoniae (16.8%), and Staphylococcus aureus (0.06%). MIC 90s for all of these organisms were well below established resistance breakpoints for moxifloxacin, indicating no bacterial resistance. On the other hand, the MIC90 for H. influenzae was 3-fold higher than the resistance breakpoint for azithromycin, ≥ 128-fold higher for S. epidermidis, 16-fold higher for S. pneumoniae and ≥ 128-fold higher for S. aureus, indicating moderate to very high bacterial resistance to azithromycin. Conclusions: Resistance to azithromycin is more common than resistance to moxifloxacin in clinical isolates causing bacterial conjunctivitis.

Original languageEnglish (US)
Pages (from-to)2241-2249
Number of pages9
JournalCurrent Medical Research and Opinion
Issue number9
StatePublished - Sep 2007


  • Azithromycin
  • Conjunctivitis
  • Fluoroquinolone
  • Macrolide
  • Moxifloxacin
  • Resistance

ASJC Scopus subject areas

  • Medicine(all)


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