September 2016
Volume 57, Issue 12
Open Access
ARVO Annual Meeting Abstract  |   September 2016
In Vitro Antibiotic Susceptibility of Ocular Pathogens Collected from the Aqueous and Vitreous Humor during the ARMOR Surveillance Study
Author Affiliations & Notes
  • Penny A Asbell
    Ophthalmology, Icahn School of Medicine at Mount Sinai, New York, New York, United States
  • Heleen H DeCory
    Medical Affairs, Bausch + Lomb, Rochester, New York, United States
  • Daniel F Sahm
    IHMA, Inc, Schaumburg, Illinois, United States
  • Christine M Sanfilippo
    Medical Affairs, Bausch + Lomb, Rochester, New York, United States
  • Footnotes
    Commercial Relationships   Penny Asbell, Bausch + Lomb (C); Heleen DeCory, Bausch + Lomb (E); Daniel Sahm, IHMA, Inc (E); Christine Sanfilippo, Bausch + Lomb (E)
  • Footnotes
    Support  None
Investigative Ophthalmology & Visual Science September 2016, Vol.57, 2348. doi:
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      Penny A Asbell, Heleen H DeCory, Daniel F Sahm, Christine M Sanfilippo; In Vitro Antibiotic Susceptibility of Ocular Pathogens Collected from the Aqueous and Vitreous Humor during the ARMOR Surveillance Study. Invest. Ophthalmol. Vis. Sci. 2016;57(12):2348.

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      © ARVO (1962-2015); The Authors (2016-present)

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Purpose : Topical antibiotics are a key part of strategies employed to minimize the incidence of intraocular infections prior to and following ocular surgery. Despite such efforts, bacterial resistance is prevalent and can reduce the effectiveness of antibiotic therapy. Here we examined resistance profiles of common bacterial pathogens isolated from the aqueous and vitreous humor to antibiotics routinely used in ophthalmic practice.

Methods : From 2009 through 2015, 172 aqueous and vitreous humor isolates were collected through the ARMOR surveillance study including 11 Haemophilus influenzae, 10 Pseudomonas aeruginosa, 21 Streptococcus pneumoniae, 30 Staphylococcus aureus, and 100 coagulase-negative staphylococci (CoNS). Minimum inhibitory concentrations (MICs) were determined by broth microdilution according to Clinical and Laboratory Standards Institute guidelines. Where applicable, isolates were categorized as susceptible, intermediate, or resistant based on systemic breakpoints.

Results : Antibiotic resistance was prevalent among staphylococci, particularly CoNS, with high rates of resistance to azithromycin (50-55%), ciprofloxacin (30-53%), and oxacillin/methicillin (33-50%). At least 70% of methicillin-resistant staphylococci demonstrated multidrug resistance (≥3 antibiotic classes). Fluoroquinolone MIC90s (in µg/mL) for CoNS, the most frequently isolated organism from the aqueous and vitreous humor, were 4, 32, 64, 64, and 256 for besifloxacin, moxifloxacin, gatifloxacin, ciprofloxacin, and levofloxacin, respectively, while ciprofloxacin was most potent against P. aeruginosa. With the exception of 1 ciprofloxacin-intermediate P. aeruginosa isolate, all P. aeruginosa and H. influenzae strains were susceptible to all agents tested. Among S. pneumoniae isolates, resistance was highest for azithromycin (33%), chloramphenicol (10%), and oral penicillin (43%).

Conclusions : Aqueous and vitreous humor staphylococcal isolates showed high levels of resistance to commonly used topical ophthalmic antibiotics. To achieve effective prophylaxis in the perioperative setting, current antibiotic resistance trends should be considered when choosing appropriate therapy.

This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.


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