title: Antibiotic resistance of ocular surface flora with repeated use of a topical antibiotic after intravitreal injection.
abstract: OBJECTIVE
  Treatment with intravitreal (IVT) injections has increased during the last several years as evidence has accumulated demonstrating the efficacy of anti-vascular endothelial growth factor agents in the treatment of neovascular age-related macular degeneration (AMD) and various retinal vascular diseases. Although IVT injections are generally safe, infectious endophthalmitis is a rare but devastating complication, and the risk of morbidity and vision loss from endophthalmitis is high.
  
  
  OBJECTIVE
  To examine the change in antibiotic resistance of ocular surface flora with repeated prophylactic use of antibiotics after IVT injection for AMD.
  
  
  METHODS
  Prospective, nonrandomized cohort study in 2 tertiary academic hospitals.
  
  
  METHODS
  Patients 65 years and older with newly diagnosed AMD were recruited by 7 retinal specialists from July 1, 2010, through December 31, 2011.
  
  
  METHODS
  The study group received topical moxifloxacin hydrochloride for 3 days after each monthly IVT injection.
  
  
  METHODS
  Resistance to moxifloxacin and ceftazidime in cultured isolates at baseline and monthly for 3 months by change in minimal inhibitory concentration (MIC) of culture isolates was studied.
  
  
  RESULTS
  The study group consisted of 84 patients, and the control group had 94 patients. In the study group, the baseline adjusted MIC increased (from 1.04 to 1.25 μg/mL; P = .01) as did the MIC for 50% of isolates (MIC50) (from 0.64 to 1.00 μg/mL) and the MIC for 90% of isolates (MIC90) (from 0.94 to 4.00 μg/mL). In both groups, the culture-positive rate did not change significantly when adjusted for baseline. No significant change was found in the MIC level, culture-positive rate, MIC50 level, and MIC90 level in the control group. Subgroup analysis found diabetes mellitus to be noncontributory to both the MIC and culture-positive rate. No endophthalmitis or adverse events were reported.
  
  
  CONCLUSIONS
  Repeated use of topical moxifloxacin after IVT injection significantly increases antibiotic resistance of ocular surface flora. We recommend that routine use of prophylactic antibiotics after IVT injection be discouraged. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT01181713.
authors: The John and Liz Tory Eye Centre, Department of Ophthalmology and Vision Sciences.
authors: Vivian T
authors: VT
authors: Yin
authors: Daniel J
authors: DJ
authors: Weisbrod
authors: Kenneth T
authors: KT
authors: Eng
authors: Carol
authors: C
authors: Schwartz
authors: Radha
authors: R
authors: Kohly
authors: Efrem
authors: E
authors: Mandelcorn
authors: Wai-Ching
authors: WC
authors: Lam
authors: Nick
authors: N
authors: Daneman
authors: Andrew
authors: A
authors: Simor
authors: Peter J
authors: PJ
authors: Kertes
mesh_terms: D000287:Administration, Topical; D000368:Aged; D000369:Aged, 80 and over; D020533:Angiogenesis Inhibitors / Q000008:administration & dosage / Q000627:therapeutic use*; D000900:Anti-Bacterial Agents / Q000008:administration & dosage*; D019072:Antibiotic Prophylaxis; D061067:Antibodies, Monoclonal, Humanized / Q000008:administration & dosage / Q000627:therapeutic use; D001372:Aza Compounds / Q000008:administration & dosage; D001419:Bacteria / Q000187:drug effects*; D002442:Ceftazidime / Q000008:administration & dosage; D015331:Cohort Studies; D003228:Conjunctiva / Q000382:microbiology*; D024901:Drug Resistance, Multiple, Bacterial; D009877:Endophthalmitis / Q000517:prevention & control*; D005260:Female; D024841:Fluoroquinolones; D006784:Hospitals, Teaching; D006801:Humans; D058449:Intravitreal Injections; D008297:Male; D008826:Microbial Sensitivity Tests; D000077266:Moxifloxacin; D011446:Prospective Studies; D011804:Quinolines / Q000008:administration & dosage; D000069579:Ranibizumab; D057135:Wet Macular Degeneration / Q000188:drug therapy*
chemical_list: D020533:Angiogenesis Inhibitors; D000900:Anti-Bacterial Agents; D061067:Antibodies, Monoclonal, Humanized; D001372:Aza Compounds; D024841:Fluoroquinolones; D011804:Quinolines; D002442:Ceftazidime; D000077266:Moxifloxacin; D000069579:Ranibizumab