Does Ocular Surface Preparation Promote Antibiotic Resistance?

Saranya C. Balasubramaniam, MD; Sophie J. Bakri, MD


January 07, 2015

Conjunctival Flora Antibiotic Resistance Patterns After Serial Intravitreal Injections Without Postinjection Topical Antibiotics

Hsu J, Gerstenblith AT, Garg SJ, Vander JF
Am J Ophthalmol. 2014;157:514.e.1-518.e.1

Study Summary

Endophthalmitis is the most serious complication of intravitreal injections. The use of postinjection antibiotics to prevent endophthalmitis and the potential for microbial resistance continue to be debated in the literature.

At most centers, the current standard preparation for intravitreal injections includes topical 5% povidone-iodine solution. However, there is little evidence supporting the efficacy of this and other biocidal agents, such as chlorhexidine, in treating conjunctival flora and resistance patterns.

The goal of this study was to determine whether repeated use of 5% povidone-iodine negatively affected conjunctival flora or altered microbial resistance patterns. Hsu and colleagues included 13 treatment-naive patients who required a series of intravitreal injections. Forty-eight conjunctival cultures were taken from these patients and analyzed, with a 77% positivity rate for at least one bacterial isolate observed. The most common bacterial isolate was coagulase-negative Staphylococcus. There was no evidence of resistance to a wide variety of antibiotics tested, including azithromycin and fluoroquinolones.


Intravitreal injections remain the standard of care for many ocular diseases. Biocidal agents, such as povidone-iodine, are frequently used to reduce the risk for endophthalmitis during intravitreal injection. This study provides evidence that ocular surface preparation with 5% povidone-iodine, in the absence of postinjection topical antibiotics, does not promote more virulent conjunctival flora or the development of resistance.



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