Susceptibility of aged mice to Staphylococcus aureus keratitis.

PURPOSE: To determine the effect of age on the extent of pathogenesis of Staphylococcus keratitis in the mouse.

METHODS

Corneas of young and aged mice (BALB/c, A/J, and C57BL/6) were scarified and topically inoculated with S. aureus. Slit lamp examination (SLE) and histopathology were performed, and bacterial colony forming units and myeloperoxidase activity were determined.

RESULTS

SLE scores of infected eyes of aged mice were significantly higher at days 1 and 3 postinfection (PI) as compared to infected young mice. Histopathological changes observed in all aged mice were more severe than those in young mice. Young BALB/c and A/J mice demonstrated minimal signs of keratitis by day 3 PI, whereas aged mice of both strains demonstrated severe keratitis by day 3. Young C57BL/6 mice showed no clinical signs of keratitis, whereas aged C57BL/6 mice demonstrated moderate keratitis.

CONCLUSIONS

Aged mice with S. aureus keratitis demonstrated increased pathology as compared to young mice.