Which combination is considered fortified antibiotics for large corneal ulcers?

• A. Tobramycin and Cefazolin
• B. Vancomycin and Cefazolin
• C. Tobramycin Alone
• D. Cefazolin Alone

Answer: (A)

Fortified topical antibiotics are used for large corneal ulcers to achieve very high local drug concentrations and broad-spectrum coverage, especially when rapid healing is needed and penetration can be challenging. The best combination pairs an aminoglycoside with a beta-lactam to cover both Gram-negative and Gram-positive bacteria effectively. Tobramycin provides strong activity against Gram-negative organisms, including Pseudomonas, while cefazolin offers robust coverage of Gram-positive cocci such as Staphylococcus and Streptococcus. Together, they deliver a wide, synergistic spectrum that is particularly important for large ulcers where mixed infections are possible and high concentrations are necessary.

Using only one antibiotic (tobramycin alone or cefazolin alone) misses either the Gram-positive or Gram-negative component, reducing effectiveness. A regimen of vancomycin with cefazolin emphasizes Gram-positive coverage (including MRSA with vancomycin) but does not provide reliable Gram-negative coverage, making it less ideal for large corneal ulcers where pseudomonal risk is significant.