Prophylaxis of bacterial pseudophakic endophthalmitis: Myth of cross-reactivity between penicillin and cefuroxime

Abstract

We read with interest the article by Pérez-Canales et al.1 on the clinical use of a vancomycin bolus administered in the anterior chamber at the end of surgery for the prevention of bacterial pseudophakic endophthalmitis. Besides expressing doubts regarding the lack of local ethical committee approval for their prospective interventional study, we should highlight the current availability of a commercially produced single-unit dose of cefuroxime, approved for intracameral use in Europe, that is now certainly to be preferred to hospital preparations because it overcomes issues related to possible contamination and incorrect dilution. This preparation was available in Europe, including Spain,A during the study period, and it might be interesting to know whether the patients were informed of the risks for possible contamination and incorrect dilution related to the use of vancomycin prepared by the local pharmacy. Likewise, the indiscriminate use of alternative vancomycin for endophthalmitis prophylaxis in cases of generic “history of allergy to penicillin” remains questionable rather than “controversial,” and patients should have been informed appropriately. We challenge the authors to agree that cross-reactivity between cefuroxime and penicillin is a myth. A recent review2 focused on the topic and found sufficient evidence to conclude that the risk for cross-reactivity between penicillin and cefuroxime (and ceftazidime) is negligible because the molecules do not share R1 side chains. In addition, given the large discrepancy between self-reported and confirmed penicillin allergies,3 it would have been more fitting to perform at least appropriate allergy testing and only include in the study patients with a documented penicillin allergy. In summary, although we ought to acknowledge that Pérez-Canales et al. have provided evidence regarding the in vivo safety of vancomycin administered intracamerally after cataract surgery, it is also very likely that an off-label alternative to intracameral cefuroxime prophylaxis treatment is not required in the vast majority of the patients; that is, patients with severe allergic reaction to other cephalosporins with a side chain similar to cefuroxime. Last, widespread use of vancomycin for prophylaxis might even cause development of bacterial resistance to this drug, currently used as a first-line agent for the treatment of pseudophakic endophthalmitis.