Antibiotics in surgery

The good news is that endophthalmitis can be prevented.” So said Per Montan MD, starting his presentation on perioperative antibiotic use in cataract surgery at the XXXV ESCRS Congress in Lisbon. Dr Montan, St Erik Hospital, Stockholm, and the National Cataract Registry, Sweden, first credited the late Dr Peter Barry, past president of the ESCRS, for his important work on endophthalmitis prophylaxis. Dr Montan addressed the two crucial components in preventing postoperative endophthalmitis: preoperative disinfection with povidone iodine and intracameral antibiotics. The role of topical antibiotics with this regime, however, is unclear. “Intracameral antibiotics have been proven to decrease the risk of endophthalmitis. A total of 24 studies, comprising six million surgeries, offer compelling evidence for the benefits of intracameral antibiotics,” he said. This includes the ESCRS endophthalmitis study, which definitively showed that cefuroxime reduced endophthalmitis rates from 0.35% in controls to 0.05% in those treated prophylactically. “However, there are still some questions that need to be answered. For example, which intracameral antibiotic is the best choice?” The prime candidates are cefuroxime, a second-generation cephalosporin, and moxifloxacin, a fourth-generation fluoroquinolone. Analysis of observational data from the Swedish National Cataract Registry did not detect a statistically significant difference in endophthalmitis rates between the two antibiotics. “Cefuroxime is effective against gram-positive strains, but it does not cover enterococci, and it is encountering resistance from methicillin-resistant staphylococci and gram negatives. On the other hand, moxifloxacin is suffering increased resistance among staphylococci and streptococci,” said Dr Montan. And although both have been shown to be safe when used correctly, with no endothelial cell loss and no increase in postoperative inflammation, there are also potential safety issues related to dosing errors. For example, if accidentally overdosed, cefuroxime can lead to transient macular oedema or even macular infarction if the concentration is sharply increased. However, a clear pattern has emerged regarding intracameral antibiotic prophylaxis. “Whatever the local ‘background rate’ of endophthalmitis with the use of topical prophylactic regimens, the rates of infection are significantly reduced upon widespread adoption of intracameral prophylaxis,” he said. “With the gold standard of preoperative disinfectants and intracameral antibiotics, it appears that a rate of one case per 5,000 surgeries might be the new benchmark for postoperative endophthalmitis. This rate is now seen in the Swedish endophthalmitis registry despite the non-use of topical antibiotics” he concluded. Per Montan: Per.montan@sankterik.se

Tags: endophthalmitis