In our health care district we had a high level of endophthalmitis. Previously, the intracamerular use of antibiotics, as we point out in the present study in group 1, lead to the incidence of endophthalmitis at a rate of 0.649%. This value is higher than that reported in other countries [2
], but the incidence in Spain was also higher than other study groups, Garcia-Saenz et al [19
] found an incidence of 0.59% (95% CI, 0.50%-0.70%) between January 1999 and September 2005, and Garat et al showed an incidence of 0.422% (95% CI 0.279-0.613) in their studies [12
]. Because our centre had an excessive number of endophthalmitis cases despite using all means of regular prophylaxis (a sterile ophthalmology operating room, povidone-iodine in skin (at 10%) and conjunctival sac (at 5%) with few surgical intraoperative complications etc.), we decided to use intracamerular antibiotics after cataract surgery.
Peyman et al. published the first report of successful prophylactic bolus injections of antibiotics into the anterior chamber in 1977 [20
]. Despite the efficacy of the injections, the technique later becomes forgotten about. It is well-established that the source of most infecting agents is the patients' ocular flora; the most frequently reported being bacteria gram-positive, coagulase-negative, or positive staphylococcus.
Swedish physicians have pioneered the use of intracameral cefuroxime since 2002, with excellent outcomes in 400,000 surgical interventions. Montan et al. published the efficacy of cefuroxime 1 mg intracameral [5
], a practice that has lowered the rate of postoperative endophthalmitis from 0.26% to 0.06%. The large, prospective, multi-centred study, the European Society of Cataract Refractive Surgeons (ESCRS) confirmed the Swedish experience, finding that an injection of cefuroxime at the end of the surgery reduced endophthalmitis rates to just 0.05% [8
We chose to use cefazolin, which is recommended by the Department of Microbiology and the Infectious Diseases Committee of our Hospital, rather than cefuroxime because it is a first generation cephalosporin and has a wide range of activity against gram-positive bacteria in our Health Care District, rather than a second-generation cephalosporin, such as cefuroxime. A study in our Health Care District by Vila-Corcoles et al [21
], showed an increased resistance of Streptococcus pneumoniae
to cefuroxime but not to cefazolin.
It is interesting to observe in Table that cefazolin and cefuroxime present a similar antibiotic resistance pattern, with regard to both gram-positive and gram-negative bacteria. Therefore, we still believe that cefazolin is a good option as a prophylaxis for endophthalmitis, and its substitution for cefuroxime is not important for reducing the number of cases of endophthalmitis. However, by using cefazolin, there is still a risk of infection by gram-negative bacteria, which is why the majority of proven cases of endophthalmitis in Group 2 (4/5 cases were gram-negative) were caused by this type of bacteria. This is clearly a limitation in the use of cefazolin as a prophylaxis for endophthalmitis.
The lack of availability of eye-drops of fourth-generation quinolones in Spain is the most obvious reason for the preference for intracamerular antibiotics in the prophylaxis of endophthalmitis. Since June 2010, a moxifloxacin eye-drop has been available in Spain, with more possibilities of prophylaxis.
Results show that final VA was worse in Group 2 than in group 1. The explanation for this can be found in the type of bacteria that cause endophthalmitis. We found Corynebacterium, Klebsiella pneumonia, Pseudomona aeroginosa, and Proteus mirabilis in group 2. All these bacteria were poorly sensitive to cefazolin. Negative culture was observed in a 34.21% of cases in group 1 and 28.57% in Group 2, similar to other studies, such as the Endophthalmitis Vitrectomy Study (EVS), with values near to 30%.