Romero-Aroca et al Dovepress (30.8% [95% CI 16.5–50.2]), and Bacillus cereus in one case In the current study, we observed that the number of (3.8% [95% CI 0.9–19.0]). The authors found a significantly endophthalmitis cases was higher in the group that used higher number of cases due to Streptococcus species than ofloxacin (0.12%) versus the azithromycin group (0.049%), after cataract surgery in the Endophthalmitis Vitrectomy resulting in a significantly increased risk of endophthalmitis Study. The percentage of cases with endophthalmitis in the of 2.37 (P , 0.001). However, the relatively low sample size current study was similar to that in the published data, at and incidence of endophthalmitis is one of the major limita- 0.049% in the azithromycin group and 0.12% in the ofloxa- tions of the study that precludes any categorical confirmation cin group. Unlike McCannel et al,26 the most commonly of the advantage of one drug over the other in the prophylaxis found bacterium (three of the four positive cases) in our of endophthalmitis after intravitreal injection. Azithromycin- study was Staphylococcus epidermidis. treated patients had a somewhat higher rate of conjunctival Because little is known about the incidence of endophthal- hyperemia, that was nevertheless seen in less than three cases mitis, it is unclear whether prophylactic antibiotics should be per 1000. There were no differences in other adverse events. used. Some authors, such as Bhatt et al,27 concluded that “the In conclusion, these findings provide a valuable addition rate of endophthalmitis after intravitreal injections admin- to the ever-increasing pool of information on endophthalmi- istered in a clinical practice setting when aseptic technique tis prophylaxis after intravitreal injection, although further is used is similar with or without the use of post injection similar large-scale studies will be required before reaching antibiotics”, but their study was based on a small number of definitive conclusions. patients. In contrast, most scientific bodies recommend the use of topical antibiotics in addition to prophylactic measures during surgery such as povidone iodine instillation on the conjunctiva, draping of the periorbital region and eyelashes, and the use of a sterile lid speculum. However, there are few recommendations on antibiotic use. The Royal College of Ophthalmologists28 recommends a dose of antibiotics before injecting the drug, while the Spanish Society of Retina and Vitreous recommends topical antibiotic treatment after injection.29 The French Agence Nationale de Sécurité du Médicament also recently recommended topical antibiotics after injection, but stated that systemic administration is not indicated.30 They advised referring to the marketing authority for the substance being injected for advice on preinjection topical antibiotic prophylaxis. Azithromycin was chosen for this study because it is a broad spectrum antibiotic that covers most commonly found bacteria in the environment and is more potent against most Gram-negative organisms than erythromycin.31,32 Furthermore, adequate and long-lasting levels were observed in the conjunctiva that remained well above the minimum inhibitory concentration (MIC) breakpoint for susceptible organisms for up to 24 hours after instillation. Residual azithromycin levels observed 7 days after the last admin- istration were above the MIC breakpoint of 0.5 µg/g in the conjunctiva and cornea. This permits topical administration twice daily for 3 days, resulting in significant concentrations in the conjunctiva and cornea for at least 7 days after final administration.33,34 Although azithromycin has poor intraocu- lar penetration when given topically, its main role is via the elimination of periocular bacteria. 1598 submit your manuscript | www.dovepress.com Dovepress Acknowledgment Editorial support was provided by Jane Irons. Disclosure The authors report no conflicts of interest in this work. References 1. Prasad AG, Schaudlu R, Apte RS. Intravitreal pharmacotherapy: applications in retinal disease. Compr Ophthalmol Update. 2007;8(5): 259–269. 2. Irigoyen C, Ziahosseini K, Morphis G, Stappler T, Heimann H. Endophthalmitis following intravitreal injections. Graefes Arch Clin Exp Ophthalmol. 2012;250(4):499–505. 3. Bodaghi B, Korobelnik JF, Cochereau I, Hajjar J, Goebel F, Dumarcet N; AFSSAPS (Association Francaise de Securite Sanitaire des Produits de Sante). Intravitreal injections: AFSSAPS guide to good practice. J Fr Ophtalmol. 2012;35(1):69–71. French. 4. Waisbourd M, Goldstein M, Loewenstein A. National survey of the ophthalmic use of anti-vascular endothelial growth factor drugs in Israel. Isr Med Assoc J. 2011;13(3):141–146. 5. Simunovic MP, Rush RB, Hunyor AP, Chang AA. Endophthalmitis following intravitreal injection versus endophthalmitis following cataract surgery: clinical features, causative organisms and post-treatment outcomes. Br J Ophthalmol. 2012;96(6):862–866. 6. Bhavsar AR, Stockdale CR, Ferris FL, Brucker AJ, Bressler NM, Glassman AR; Diabetic Retinopathy Clinical Research Network FT. Update on risk of endophthalmitis after intravitreal drug injections and potential impact of elimination of topical antibiotics. Arch Ophthalmol. 2012;130(6):809–810. 7. Angulo Bocco MC, Glacet-BernardA, ZourdaniA, Coscas G, Soubrane G. Intravitreous injection: retrospective study on 2028 injections and their side effects. J Fr Ophtalmol. 2008;31(7):693–698. French. 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. Moshfeghi AA, Rosenfeld PJ, Flynn HW Jr, et al. Endophthalmitis after intravitreal anti-vascular endothelial growth factor antagonists: a six-year experience at a university referral center. Retina. 2011;31(4): 662–668. Clinical Ophthalmology 2012:6