Spontaneous sterilization in experimental Staphylococcus epidermidis endophthalmitis.

We created a standardized model of endophthalmitis in the aphakic rabbit eye using a laboratory strain of Staphylococcus epidermidis of known characteristics (ATCC 155). Eyes were injected with the following number of organisms: 170, 3760, 8750, 170,000 and 460,000. Serial quantitative cultures, clinical grading of infection and histopathologic studies were performed on days 1, 2, 3, 7 and 14. Bacteria appeared to multiply rapidly during the first 24 hr with peak recovery at 8 to 24 hr. Fewer bacteria were cultured on the third day after injection, and positive cultures were rare after the third day. Inflammatory scores were initially higher with each increased number of injected bacteria and tended to increase for the first 3 to 5 days.