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Ulcerative keratitis. Survey of 30 years' laboratory experience
Abstract:
During a 30-year period, causative organisms were identified on Gram's stain and culture in 547 of 677 cases of infectious corneal ulcers. Even if no organisms were seen on Gram's stain, culture results were often positive. Staphylococcus was the most common isolate; Moraxella, Pseudomonas, and Streptococcus pneumoniae were the next most frequent pathogens. Only 1% of cases were fungal. Of some help in identifying the causative organism were locations, presence or absence of hypopyon, and perforation of the ulcer. Most marginal lesions were a result of staphylococcal infection; central lesions were more likely to be Gram-negative ulcers. Fungal ulcers were identified by laboratory workup and not by clinical characteristics. Moraxella infection was observed almost exclusively in malnourished patients. Pseudomnas ulcers were often seen in patients with large body burns or patients receiving respiratory assistance. Gentamicin and neomycin were the most effective treatments.
Insights
Identifying causative organisms in infectious corneal ulcers is crucial. Staphylococcus was most common, while clinical features aided diagnosis for some bacteria but not fungi.
Area of Science:
- Ophthalmology
- Microbiology
Background:
- Infectious corneal ulcers are a significant cause of vision loss.
- Accurate identification of causative pathogens is essential for effective treatment.
Purpose of the Study:
- To identify the causative organisms of infectious corneal ulcers over a 30-year period.
- To correlate clinical features with specific pathogens.
- To evaluate treatment efficacy.
Main Methods:
- Analysis of Gram's stain and culture results from 677 cases of infectious corneal ulcers.
- Correlation of clinical data (ulcer location, hypopyon, perforation) with identified organisms.
- Review of treatment outcomes.
Main Results:
- Causative organisms were identified in 547 cases (81%).
- Staphylococcus was the most frequent isolate, followed by Moraxella, Pseudomonas, and Streptococcus pneumoniae.
- Clinical features were helpful in identifying bacterial ulcers but not fungal ulcers.
- Moraxella infections were linked to malnutrition; Pseudomonas infections to burns or respiratory support.
- Gentamicin and neomycin showed the most effectiveness.
Conclusions:
- Gram's stain and culture are vital for diagnosing infectious keratitis.
- Specific clinical signs can suggest certain bacterial pathogens.
- Fungal ulcers require laboratory confirmation.
- Targeted antibiotic therapy is crucial for successful outcomes.