Ocular Microbiology and Immunology Group
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2013 OMIG Abstract 14

Biofilm-related Infections of the Boston Keratoprosthesis
Irmgard Behlau^1,2, Ann S. Tisdale¹, Elizabeth Leonard¹, Frederick A. Jakobiec¹,
Joseph Tauber³, and Claes H. Dohlman^1
1Ophthalmology, Massachusetts Eye and Ear Infirmary/Schepens Eye Research Institute, Boston, MA,
²Molecular Biology & Microbiology and Ophthalmology, Tufts University School of Medicine, Boston, MA,
³Tauber Eye Center, Kansas University School of Medicine, Kansas City, MO

Purpose: To define the role of biofilms in infections and corneal melts associated with the Boston keratoprosthesis using clinical, microbiologic, and scanning electron microscopy criteria.

Methods: Nine explanted Boston keratoprosthesis were collected over a three-year period. Medical chart reviews were performed to determine risk factors, antimicrobial prophylactic regimens, microbiological etiologies, and visual outcomes. One explanted eye underwent histopathological examination. Scanning electron microscopy was performed on all explanted Boston KPros.

Results: Seven explanted keratoprosthesis were removed, while two self-extruded in response to infection. All patients received topical prophylactic antibiotics and one-third received systemic antimicrobials prior to Boston KPro removal. Four explanted B-KPros were found to have active biofilm-related infections by scanning electron microscopy and microbiological cultures. Organisms identified included Streptococcus pyogenes, Streptococcus mitis, Staphylococcus aureus, and Candida albicans. One B-KPro was explanted pre-emptively due to prior filamentous fungal cultures; there was no evidence of infection. Four explanted
B-KPros due to corneal melt in autoimmune patients proved to be sterile with inflammatory tissue responses.   

Conclusions: Viable biofilms were identified despite use of prophylactic antibiotics and they were found in areas most inaccessible to maximal antibiotic penetration – under the front plate, along the B-KPro stem, and on the posterior surface of the corneal graft. Loss of device-tissue interface was seen in both the biofilm-related infections and in the autoimmune-related corneal melts. Insight gained from this study may guide antibiotic prophylactic regimens and future antimicrobial coating surface modifications. 

Funding: Fight-for-Sight Grant-in-Aid (IB) and MEEI Boston KPro Fund

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