Quantitation of bacterial infection and antibiotic effect in the cornea.

We report an experimental model that allows objective quantitation of bacterial keratitis. The model permits direct measurement of the number of viable organisms in the cornea after varying periods of in vivo growth. The size of the inoculum used to produce the corneal infection is critical, and the experimental organism must be standardized for its growth characteristics in the cornea. The end point is an objective one, productive of numerical data that can be subjected to statistical analysis. The findings are highly reproducible and the system is sufficiently sensitive to indicate the ability of a topically administered antibiotic to reduce the number of viable organisms in the cornea of an outbred rabbit population.