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Factors influencing predilection and outcome in bacterial keratitis
O G Gudmundsson1, L D Ormerod, K R Kenyon
1Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston 02114.
Abstract:
Complete records from 175 patients with 176 episodes of culture-proven bacterial keratitis treated over a 4-year period at the Massachusetts Eye and Ear Infirmary in Boston were analyzed. Sixty-three percent of the infections involved gram-positive organisms, and 40% involved gram-negative organisms; 15% were polymicrobial. There was a high incidence of infection with Staphylococcus aureus (28%), coagulase-negative staphylococci (14%), diphtheroids (14%), Pseudomonas aeruginosa (14%), and Streptococcus pneumoniae (12%). Gram stain correlation was achieved in 55%. Potential predisposing factors, usually multiple, were identified in 97% of the patients. Fifty percent of the ulcers were associated with such iatrogenic factors as prior topical corticosteroid therapy, penetrating keratoplasty, and contact lens use. Trauma occurred in only 16%. Several statistically significant associations of epidemiologic factors and outcome variables were revealed. Ninety-five percent of the ulcers resolved with therapy, but only 44% of the patients had visual acuity better than the level at admission, and 13% developed major complications.
Insights
Bacterial keratitis, an eye infection, often involves Gram-positive and Gram-negative bacteria, with Staphylococcus aureus being common. While most ulcers heal, many patients experience no vision improvement and some develop complications.
Area of Science:
- Ophthalmology
- Microbiology
- Infectious Diseases
Background:
- Bacterial keratitis is a significant cause of ocular morbidity.
- Understanding causative organisms and predisposing factors is crucial for effective management.
Purpose of the Study:
- To analyze the epidemiology and outcomes of bacterial keratitis.
- To identify common pathogens and associated risk factors.
Main Methods:
- Retrospective analysis of 176 culture-proven bacterial keratitis episodes.
- Data collection on patient demographics, clinical presentation, microbiology, and treatment outcomes.
Main Results:
- Gram-positive organisms (63%) and Gram-negative organisms (40%) were frequently identified.
- Staphylococcus aureus (28%) was a leading pathogen; 97% of patients had predisposing factors.
- While 95% of ulcers resolved, only 44% achieved improved visual acuity, and 13% had major complications.
Conclusions:
- Bacterial keratitis presents with diverse microbial profiles and numerous predisposing factors.
- Despite high ulcer resolution rates, visual outcomes are often suboptimal, highlighting the need for improved prevention and treatment strategies.