Conjunctival flora antibiotic resistance patterns after serial intravitreal injections without postinjection topical antibiotics

Am J Ophthalmol. 2014 Mar;157(3):514-8.e1. doi: 10.1016/j.ajo.2013.10.003. Epub 2013 Oct 19.


Purpose: To report conjunctival bacterial flora antibiotic resistance patterns after serial intravitreal injections performed using a povidone-iodine preparation without the use of preinjection or postinjection topical antibiotics.

Design: Prospective, interventional case series.

Setting: Single-center clinical practice in Pennsylvania.

Study population: Thirteen eyes of 13 treatment-naïve patients undergoing serial intravitreal anti-vascular endothelial growth factor (VEGF) injections for exudative age-related macular degeneration or macular edema attributable to retinal vein occlusion.

Intervention: Conjunctival cultures from the treatment eye were performed prior to each injection preparation. A minimum of 3 monthly conjunctival cultures were obtained per eye over the course of the study. Ocular surface preparation consisted of topical anesthetic and povidone-iodine 5% without the use of preinjection or postinjection topical antibiotics.

Main outcome measures: Conjunctival flora growth patterns and antibiotic resistance patterns to several common antibiotics tested over the course of the study.

Results: A total of 48 cultures were performed with a 77% culture positivity rate. Over the course of the serial conjunctival cultures in each patient, there was no evidence for emergence of resistant bacteria to any of the tested antibiotics (including fluoroquinolones and azithromycin) or significant alteration from baseline conjunctival flora. Of the 47 bacterial isolates, the most commonly isolated organism was coagulase-negative Staphylococcus both at baseline (73%) and following serial intravitreal injections (78%, P = .73).

Conclusions: Ocular surface preparation for intravitreal injection using povidone-iodine 5% alone in the absence of postinjection topical antibiotics does not appear to promote bacterial resistance or a discernible change in conjunctival flora.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Administration, Topical
  • Adult
  • Aged
  • Aged, 80 and over
  • Angiogenesis Inhibitors / therapeutic use*
  • Anti-Bacterial Agents / administration & dosage
  • Anti-Infective Agents, Local / therapeutic use*
  • Antibiotic Prophylaxis
  • Bacteria / drug effects
  • Bacteria / isolation & purification*
  • Conjunctiva / microbiology*
  • Drug Resistance, Bacterial*
  • Endophthalmitis / microbiology
  • Endophthalmitis / prevention & control
  • Female
  • Humans
  • Intravitreal Injections
  • Macular Edema / drug therapy
  • Male
  • Microbial Sensitivity Tests
  • Middle Aged
  • Povidone-Iodine / therapeutic use*
  • Prospective Studies
  • Vascular Endothelial Growth Factor A / antagonists & inhibitors
  • Wet Macular Degeneration / drug therapy


  • Angiogenesis Inhibitors
  • Anti-Bacterial Agents
  • Anti-Infective Agents, Local
  • VEGFA protein, human
  • Vascular Endothelial Growth Factor A
  • Povidone-Iodine