Sir,

I read with great interest Fernández-Rubio et al’s1 study on colonization patterns in relation to systemic co-morbidities.

There appears to be, however, a misconception between the usage of intracameral cefuroxime and its perceived protective effect against PE secondary to enterococci. Cefuroxime is a second-generation cephalosporin with an intrinsic lack of activity against enterococci owing to the production of low-affinity penicillin binding proteins and L,D-transpeptidase.2, 3 This is commonly referred to as the ‘enterococci-gap’.

Putting this into the broader picture of the quoted EVS4 vs the Swedish National Cataract Register Study,5 the a priori lack of efficiency of cefuroxime against enterococci explains the higher prevalence of enterococci-induced PE in the Swedish group (29.9% vs 2.2%) and is not surprising.

Given that enterococci-induced PE is a considerable problem in the era of intracameral cefuroxime, it seems counterintuitive that the authors’ standard choice for topical preoperative prophylaxis is a combination of Polymyxin B and Trimethoprim, both of which have low effectiveness against enterococci. Topical Chloramphenicol would seem a superior choice in this context.

It would have been interesting to know which species of bacteria the cluster of four PEs in 2005/2006 belonged to and whether intracameral cefuroxime had been given.

It would also be interesting to know which oral antibiotic prophylaxis was chosen in those cases that displayed enterococci in their conjunctival flora.

As no intraocular samples were taken, it remains unclear how the authors arrive at the conclusion that the ‘risk of intraocular contamination... was increased 1.6 and 2.5 times in those over 85 and 90...’.