title: Incidence of endophthalmitis and use of antibiotic prophylaxis after intravitreal injections.
abstract: OBJECTIVE
  To report the incidence of endophthalmitis in association with different antibiotic prophylaxis strategies after intravitreal injections of anti-vascular endothelial growth factors and triamcinolone acetonide.
  
  
  METHODS
  Retrospective, comparative case series.
  
  
  METHODS
  Fifteen thousand eight hundred ninety-five intravitreal injections (9453 ranibizumab, 5386 bevacizumab, 935 triamcinolone acetonide, 121 pegaptanib sodium) were reviewed for 2465 patients between January 5, 2005, and August 31, 2010. The number of injections was determined from billing code and patient records.
  
  
  METHODS
  The indications for injection included age-related macular degeneration, diabetic macular edema, central and branch retinal vein occlusion, and miscellaneous causes. Three strategies of topical antibiotic prophylaxis were used by the respective surgeons: (1) antibiotics given for 5 days after each injection, (2) antibiotics given immediately after each injection, and (3) no antibiotics given.
  
  
  METHODS
  The primary outcome measures were the incidence of culture-positive endophthalmitis and culture-negative cases of suspected endophthalmitis.
  
  
  RESULTS
  Nine eyes of 9 patients with suspected endophthalmitis after injection were identified. Three of the 9 cases had culture-positive results. The overall incidence of endophthalmitis was 9 in 15 895. The incidence of culture-negative cases of suspected endophthalmitis and culture-proven endophthalmitis after injection was 6 in 15 895 and 3 in 15 895, respectively. Taking into account both culture-positive endophthalmitis and culture-negative cases of suspected endophthalmitis, the incidence per injection was 5 in 8259 for patients who were given antibiotics for 5 days after injection, 2 in 2370 for those who received antibiotics immediately after each injection, and 2 in 5266 who received no antibiotics. However, if considering culture-proven endophthalmitis alone, the use of topical antibiotics, given immediately or for 5 days after injection, showed lower rates of endophthalmitis compared with those without postinjection antibiotics. The risk of endophthalmitis after intravitreal injection varied among agents that were used. Among the 9 cases of clinically suspected endophthalmitis, regardless of prophylactic strategies used, the incidence of endophthalmitis per injection was 2 in 935 for triamcinolone acetonide, 3 in 9453 for ranibizumab, and 4 in 5386 for bevacizumab.
  
  
  CONCLUSIONS
  The overall rate of intravitreal injection-related endophthalmitis is greater with the use of topical antibiotics, given immediately or for 5 days after the injection, compared with no antibiotics.
authors.affiliation: Department of Ophthalmology and Vision Sciences, University Health Network/Toronto Western Hospital, Toronto, Canada.
authors.forename: Crystal S Y
authors.initials: CS
authors.lastname: Cheung
authors.forename: Amanda W T
authors.initials: AW
authors.lastname: Wong
authors.forename: Alex
authors.initials: A
authors.lastname: Lui
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Kertes
authors.forename: Robert G
authors.initials: RG
authors.lastname: Devenyi
authors.forename: Wai-Ching
authors.initials: WC
authors.lastname: Lam
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000779:Anesthetics, Local / Q000008:administration & dosage; D020533:Angiogenesis Inhibitors / Q000008:administration & dosage*; D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D019072:Antibiotic Prophylaxis / Q000379:methods*; D003930:Diabetic Retinopathy / Q000188:drug therapy; D009877:Endophthalmitis / Q000453:epidemiology* / Q000382:microbiology; D005260:Female; D024841:Fluoroquinolones / Q000627:therapeutic use*; D005938:Glucocorticoids / Q000008:administration & dosage*; D006801:Humans; D015994:Incidence; D058449:Intravitreal Injections; D008268:Macular Degeneration / Q000188:drug therapy; D008269:Macular Edema / Q000188:drug therapy; D008297:Male; D008875:Middle Aged; D012170:Retinal Vein Occlusion / Q000188:drug therapy; D012189:Retrospective Studies; D012307:Risk Factors; D014222:Triamcinolone Acetonide / Q000008:administration & dosage; D042461:Vascular Endothelial Growth Factor A / Q000037:antagonists & inhibitors; D014792:Visual Acuity / Q000502:physiology
chemical_list: D000779:Anesthetics, Local; D020533:Angiogenesis Inhibitors; D000900:Anti-Bacterial Agents; D024841:Fluoroquinolones; D005938:Glucocorticoids; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A; D014222:Triamcinolone Acetonide