Route of antibiotic administration in bacterial keratitis.

The in vivo antibacterial effectiveness in the rabbit cornea of several antibiotics delivered by topical application, by periocular injection, and by intravenous (IV) inoculation was determined against Staphylococcus aureus and Pseudomonas aeruginosa. Topical instillation of antibiotic was highly effective in eliminating these organisms from the cornea. In contrast, despite a considerable increase in the quantity of antibiotic administered, we could demonstrate no statistically significant reduction in the number of viable staphylococcal or Pseudomonas organisms in the cornea when the antibiotic was given by periocular or by IV injection.