Prophylaxis of Pseudophakic Endophthalmitis with Topical Antibiotics

Dear Editor:

In their recent article, ¹ Dr. Kowalski et al. addressed an important and delicate aspect of intraocular surgery, that is, the prevention of postoperative endophthalmitis, a severe adverse event. ²

Their experimental study on rabbits was designed and conducted to verify the hypothesis that topical fluoroquinolones (FQs) are superior to other antibiotics in preventing the occurrence of endophthalmitis. Besides demonstrating this, they also observed the inefficacy of the postoperative topical treatment with chloramphenicol in the prevention of postoperative endophthalmitis, meeting the conclusions of a recent retrospective clinical study. ³ This is valuable information, and it may likely change the clinical practice, as chloramphenicol is still widely prescribed after cataract surgery.^4,5

In addition, while acknowledging that the current gold standard in antibiotic prophylaxis is represented by the topical application of povidone-iodine, the authors also suggested that FQs would be of particular importance in cases for those at risk of postoperative endophthalmitis due to an inadequate surgical preparation or poor surgical technique, and therefore the application of topical anti-infectives to penetrate into the aqueous appears to be a reasonable added safety measure.

The study design and the authors' conclusions leave a number of considerations to be made. First, given the adopted methods (direct inoculation of bacteria into the anterior chamber), the study design should have not included povidone-iodine, as it does not penetrate through the cornea, with the significant inferiority to FQs in preventing endophthalmitis in this study being largely expected. Also, it would be recommendable to avoid an elective intraocular surgery in the presence of conjunctivitis, blepharitis, or mucous discharge secondary to the lacrimal system pathology, and it would be unacceptable to cover the increased risk of infection due to either a poor surgical technique or a poor operating field preparation with the adoption of an additional treatment. Finally, given that the rate of pseudophakic endophthalmitis was found to be lower than 0.06% in the absence of any postoperative topical antibiotic treatment,^3,6 there are 2 major concerns with the authors' suggested approach: the antibiotic resistance and the cost–effectiveness of FQs. On one side, detailed and accurate cost analyses have shown that topical fourth-generation FQs would have to be ≥19 times more effective than intracameral cefuroxime to achieve the cost–effectiveness equivalence. ⁷ On the other hand, the importance of prudent prescribing to reduce the occurrence of resistance to quinolones has been previously stressed, ⁸ and the emerging resistance of ocular pathogens to FQs reinforces the concerns with their routine use.^9–11 Noteworthy, the systemic fourth-generation FQs are currently an effective therapeutic weapon in cases of pseudophakic endophthalmitis, which we might lose should the resistance rates to these antibiotics increase.