Related Experiment Videos
Gentamicin resistance in staphylococcal corneal ulcers
T H Mader1, K L Maher, R D Stulting
1Department of Ophthalmology, Emory University School of Medicine, Atlanta, Georgia 30322.
Cornea
|September 1, 1991
Summary
Staphylococcal keratitis (corneal ulcers) showed high resistance to gentamicin. Initial treatment for suspected staphylococcal keratitis should include antibiotics effective against Gram-positive bacteria, like cephalosporins or vancomycin.
Area of Science:
- Ophthalmology
- Microbiology
- Infectious Diseases
Background:
- Gentamicin sulfate is a common first-line antibiotic for bacterial keratitis.
- Staphylococcal infections are a significant cause of corneal ulcers.
Purpose of the Study:
- To evaluate gentamicin susceptibility of staphylococci isolated from corneal ulcers.
- To inform optimal initial antibiotic therapy for bacterial keratitis.
Main Methods:
- Collected corneal ulcer isolates from nine patients.
- Performed standard disk diffusion susceptibility testing for gentamicin.
- Determined minimum inhibitory concentrations (MICs) for gentamicin.
Main Results:
- All coagulase-negative staphylococci and Staphylococcus aureus isolates were resistant to gentamicin via disk diffusion.
- MICs for gentamicin were very high, often exceeding achievable topical concentrations.
- Demonstrated significant gentamicin resistance in staphylococcal keratitis pathogens.
Conclusions:
- Strains of staphylococci highly resistant to gentamicin can cause microbial keratitis.
- Current gentamicin monotherapy may be ineffective for staphylococcal keratitis.
- Initial empiric therapy for suspected staphylococcal keratitis should include broad-spectrum Gram-positive coverage (e.g., cephalosporin, vancomycin).