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Microbial keratitis complicating penetrating keratoplasty
L P Fong1, L D Ormerod, K R Kenyon
1Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston.
Abstract:
A retrospective review of 68 consecutive episodes of microbial keratitis complicating 66 penetrating keratoplasties (PKs) showed major risk associations: suture-related problems (50%), contact lens wear (26%), previous herpes simplex infection (15%), graft failure (15%), and persistent epithelial defects (15%). Topical steroid (85%) and antibiotic (59%) usage were common iatrogenic factors. Half the infections occurred more than 1 year after grafting. Bacterial infections involving gram-positive organisms (59%) predominated, except for patients with extended-wear hydrophilic contact lenses, which usually involved gram-negative bacilli. The incidence of fungal infections (6%) was relatively low. Recommendations to minimize microbial keratitis include prompt attention to exposed, broken, or loose sutures, and preventive and therapeutic management of epithelial defects. The inadequacy of low-dose antibiotics in precluding microbial infection in many cases and the propensity to develop infections with resistant organisms suggest that guidelines for using postoperative and prophylactic topical antibiotics require reevaluation.
Insights
Microbial keratitis after penetrating keratoplasty (PK) is often linked to suture issues and contact lens wear. Reevaluating antibiotic use is crucial to prevent infections, especially those with resistant organisms.
Area of Science:
- Ophthalmology
- Infectious Diseases
Background:
- Microbial keratitis is a serious complication following penetrating keratoplasty (PK).
- Identifying risk factors and causative organisms is essential for effective management and prevention.
Purpose of the Study:
- To identify major risk factors associated with microbial keratitis after PK.
- To analyze the timing, microbial profiles, and iatrogenic factors contributing to these infections.
- To provide recommendations for minimizing the incidence of microbial keratitis post-PK.
Main Methods:
- Retrospective review of 68 episodes of microbial keratitis in 66 patients who underwent PK.
- Analysis of associated risk factors, iatrogenic causes, and microbial organisms.
Main Results:
- Major risk factors included suture problems (50%), contact lens wear (26%), and previous herpes simplex infection (15%).
- Topical steroids (85%) and antibiotics (59%) were common iatrogenic factors.
- Bacterial infections, predominantly gram-positive, were most common; gram-negative bacilli were associated with extended-wear contact lenses. Fungal infections were rare (6%).
- Half of the infections occurred over a year post-grafting.
Conclusions:
- Prompt management of suture-related issues and epithelial defects is critical.
- Current antibiotic guidelines may be inadequate, necessitating a reevaluation to address resistant organisms and prevent infections.