Abstract
Purpose: :
To determine the influence of topical antibiotic drops on the microbiologic flora of the conjunctiva and contact lenses in eyes with a Boston Keratoprosthesis (KPro).
Methods: :
A prospective cohort study was performed for 14 eyes of 13 patients who received a KPro between 9/2005 and 6/2011. Preoperative diagnoses included failed corneal grafts, limbal stem cell deficiency, chemical burns, and Stevens-Johnson Syndrome (SJS). Patients used topical antibiotic prophylaxis after KPro surgery including a fluoroquinolone, polymyxin-trimethoprim, vancomycin, or a combination of the three. Patients were screened and invited to the study if they had a KPro, and were on a prophylactic antibiotic. The conjunctiva of the inferior fornix in the study eye was swabbed with a sterile swab and subsequently cultured. A separate swab and culture was taken of the contralateral eye to serve as a control. If available, the contact lens was removed with sterile forceps with half placed in thioglycolate broth, and the other half in 5cc of sterile balanced salt solution (BSS). The contact lens in BSS was sonicated using a QSonica Q125 sonicator (Newtown, CT) for 1 minute, at an amplitude of 20. Ten microliters of fluid was subsequently cultured.
Results: :
Of the patients that underwent KPro surgery during that time period, 14 eyes from 13 patients were able to participate in the data collection. Eight out of 14 KPro eyes (57%) had no growth. 3 eyes grew coagulase negative staphylococcus, 1 eye grew streptococcus viridans, 1 eye grew Klebsiella pneumoniae, and 1 eye grew multiple bacterial organisms. None of the swabs grew fungal organisms. Results from contact lens sonication were comparable.
Conclusions: :
Polymyxin-trimothoprim alone may not be adequate bacterial prophylaxis for KPro eyes. A fluoroquinolone and/or topical vancomycin may improve sterilization of conjunctival flora in KPro eyes. None of the cultures grew resistant organisms, even in the context of chronic topical antibiotic therapy. Sonication of the contact lens may be an adequate method of culturing the biofilm from a contact lens.
Keywords: keratoprostheses • cornea: basic science • contact lens