The Role of Topical Antibiotics for Intravitreal Injections
The mainstay of treatment of exudative age-related macular degeneration (AMD) is intravitreal injection of an anti-VEGF agent. It is estimated that over 1 million intravitreal injections are performed annually.1 The majority of patients receive multiple injections. The most serious complication of this procedure is endophthalmitis. The endophthalmitis risk following intravitreal injection is estimated to be 0.04%-0.048%.2,3 Various measures have been reported to try to reduce the risk of endophthalmitis. These include prophylactic topical antibiotics, sterile drapes, sterile gloves, face mask, eyelid speculum, and topical povidone-iodine.
Traditionally, topical antibiotics have been used to try to prevent infection following intraocular procedures such as vitrectomy and cataract surgery. When intravitreal injection became the standard of care for patients with exudative AMD, topical antibiotics were widely employed to try to prevent endophthalmitis. Many of the strategies used to try to prevent post-injection endophthalmitis are controversial. Topical povidone-iodine is the only measure that has been documented to prevent endophthalmitis.4,5 Topical antibiotics have been shown to decrease the bacterial flora in the conjunctiva but this has not translated into a decreased risk of endophthalmitis.6-8 In fact, several studies have demonstrated a similar or slightly increased risk of endophthalmitis with the use of topical antibiotics.7,8 There is also the concern of promoting bacterial resistance of ocular surface flora with repeated exposure to topical antibiotics. Some studies have reported that antimicrobial resistance of ocular surface flora may double as a result of repeated exposure to topical antibiotics.9,10 Further, the composition of conjunctival flora changes after repeated exposure to topical antibiotics following intravitreal injection. Dave et al reported that repeated application of macrolide or fluoroquinolone antibiotics following intravitreal injection increases the percentage of S epidermidis (one of the most commonly identified opportunistic pathogens) in ocular flora.11 This could have significant clinical implications since millions of intravitreal injections are performed each year and the number is likely to continue to increase.
In 2007, Bhavsar et al reported on the low rate of endophthalmitis in the DRCRnet and SCORE studies (1 in 2009 [0.05%]) without prescribing antibiotic prophylaxis on the days prior to the injection.12 In 2009, the DRCRnet study group reported no cases of endophthalmitis in patients receiving no antibiotics and an endophthalmitis rate of 0.09% in patients receiving antibiotics for several days after the intravitreal injection.13 In the 2013 American Society of Retina Specialists (ASRS) Preferences and Trends (PAT) survey, 78.2% of respondents reported not using an antibiotic with intravitreal injection, 2.7% employed a topical antibiotic before and after intravitreal injection, 1.5% instilled a topical antibiotic before intravitreal injection, and 9.7% employed a topical antibiotic only after intravitreal injection.
In summary, there is a lack of evidence to support the hypothesis that topical antibiotics (pre-injection or post-injection) decrease the risk of endophthalmitis following intravitreal injection. Povidone-iodine has been shown to be bactericidal and effective in preventing endophthalmitis. Further, repeated exposure to topical antibiotics has been demonstrated to promote the development of antimicrobial resistance and alter the composition of ocular surface flora. Therefore, and as reported previously,14 topical antibiotics should no longer be considered standard of care for prevention of endophthalmitis. The more cost-effective 5% povidone-iodine should be used as endophthalmitis prophylaxis for intravitreal injections.
1. Peyman GA, Lad EM, Moshfeghi DM. Intravitreal injection of therapeutic agents. Retina. 2009 Jul-Aug;29(7):875-912.
2. Tabandeh H, Boscia F, Sborgia A, Ciracì L, Dayani P, Mariotti C, Furino C, Flynn HW Jr. Endophthalmitis associated with intravitreal injections: office-based setting and operating room setting. Retina. 2014 Jan;34(1):18-23.
3. Storey P, Dollin M, Pitcher J, Reddy S, Vojtko J, Vander J, Hsu J, Garg SJ; Post-Injection Endophthalmitis Study Team. The role of topical antibiotic prophylaxis to prevent endophthalmitis after intravitreal injection. Ophthalmology. 2014 Jan;121(1):283-289
4. Speaker MG, Menikoff JA. Prophylaxis of endophthalmitis with topical povidone-iodine. Ophthalmology. 1991 Dec;98(12):1769-1775.
5. Berkelman RL, Holland BW, Anderson RL. Increased bactericidal activity of dilute preparations of povidone-iodine solutions. J Clin Microbiol. 1982 Apr;15(4):635-9.
6. Moss JM, Sanislo SR, Ta CN. A prospective randomized evaluation of topical gatifloxacin on conjunctival flora in patients undergoing intravitreal injections. Ophthalmology. 2009;116:1498–501.
7. Bhatt SS, Stepien KE, Joshi K. Prophylactic antibiotic use after intravitreal injection: effect on endophthalmitis rate. Retina. 2011;31:2032–6.
8. Cheung CS, Wong AW, Lui A, Kertes PJ, Devenyi RG, Lam WC. Incidence of endophthalmitis and use of antibiotic prophylaxis after intravitreal injections. Ophthalmology. 2012;119(8):1609-1614.
9. Kim SJ, Toma HS. Ophthalmic antibiotics and antimicrobial resistance a randomized, controlled study of patients undergoing intravitreal injections. Ophthalmology. 2011;118(7):1358-1363
10. Kim SJ, Toma HS. Antimicrobial resistance and ophthalmic antibiotics: 1-year results of a longitudinal controlled study of patients undergoing intravitreal injections. Arch Ophthalmol. 2011;129(9):1180-1188
11. Sarita B. Dave, MD, Hassanain S. Toma, MD, Stephen J. Kim, MD. Changes in ocular flora in eyes exposed to ophthalmic antibiotics. Ophthalmology. 2013 May;120(5):937-41
12. Bhavsar AR, Ip MS, Glassman AR; DRCRnet and the SCORE Study Groups. The risk of endophthalmitis following intravitreal triamcinolone injection in the DRCRnet and SCORE clinical trials. Am J Ophthalmol. 2007 Sep;144(3):454-6.
13. Bhavsar AR, Googe JM Jr, Stockdale CR, Bressler NM, Brucker AJ, Elman MJ, Glassman AR; Diabetic Retinopathy Clinical Research Network. Risk of endophthalmitis after intravitreal drug injection when topical antibiotics are not required: the diabetic retinopathy clinical research network laser-ranibizumab-triamcinolone clinical trials. Arch Ophthalmol. 2009 Dec;127(12):1581-3.
14. Chen RWS, Rachitskaya A, Scott IU, Flynn HW Jr. Is the use of topical antibiotics for intravitreal injections the standard of care or are we better off without antibiotics? JAMA Ophthalmol. 2013;131(7):840-842.
About our author(s):
Esther Bowie, MD
Associate Professor of Ophthalmology
Penn State Milton S. Hershey Medical Center