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Abstract:
In a series of 162 bacterial corneal ulcers, 27 were culture positive for anaerobic organisms. Applying strict microbiologic criteria, 11 ulcers were determined to be due to anaerobic infection. No morphologic characteristic was identified to distinguish anaerobic from other types of corneal ulcers. All of the anaerobic ulcer patients manifested one or more predisposing factors. A total of 13 anaerobes were cultured from the 11 confirmed anaerobic ulcers. Five previously unreported anaerobic strains were identified as causes of bacterial keratitis. Over one third of the anaerobic organisms occurred in mixed cultures with other organisms. Most of the anaerobic isolates were susceptible to all antibiotics routinely used for their treatment. The use of topical chloramphenicol is recommended for treatment of confirmed anaerobic ulcers, and topical cefazolin or one of the other cephalosporins effective against anaerobes is suggested to be included in the treatment of all ulcers requiring broad spectrum antibiotic coverage.
Insights
Anaerobic bacteria can cause serious corneal ulcers, often with predisposing factors. Most anaerobic isolates were susceptible to common antibiotics, with chloramphenicol recommended for treatment.
Area of Science:
- Ophthalmology
- Microbiology
Background:
- Bacterial keratitis is a significant cause of vision loss.
- Anaerobic bacteria are less commonly recognized causes of corneal ulcers.
Purpose of the Study:
- To identify the prevalence and characteristics of anaerobic bacterial keratitis.
- To determine predisposing factors and effective treatments for anaerobic corneal ulcers.
Main Methods:
- Retrospective analysis of 162 bacterial corneal ulcers.
- Strict microbiologic criteria for confirming anaerobic infection.
- Identification of anaerobic isolates and antibiotic susceptibility testing.
Main Results:
- 11 of 162 ulcers (6.8%) were confirmed anaerobic bacterial keratitis.
- Predisposing factors were present in all anaerobic ulcer patients.
- Five new anaerobic strains were identified as causes of keratitis.
- Most anaerobic isolates showed susceptibility to routine antibiotics.
Conclusions:
- Anaerobic bacteria are an underrecognized cause of bacterial keratitis.
- Topical chloramphenicol is recommended for confirmed anaerobic ulcers.
- Broad-spectrum antibiotics including cephalosporins effective against anaerobes are advised for all severe ulcers.