A new topical model of Staphylococcus corneal infection in the mouse.

Dalia Girgis // Publications // Apr 01 2003

PubMed ID: 12657597

Author(s): Girgis DO, Sloop GD, Reed JM, O’Callaghan RJ. A new topical model of Staphylococcus corneal infection in the mouse. Invest Ophthalmol Vis Sci. 2003 Apr;44(4):1591-7. PMID 12657597

Journal: Investigative Ophthalmology & Visual Science, Volume 44, Issue 4, Apr 2003

PURPOSE To establish, in the scarified mouse eye, a new model of Staphylococcus aureus keratitis suitable for studies of pathogenesis and host defense mechanisms.

METHODS Corneas of three strains of mice (BALB/c, A/J, and C57BL/6) were scarified and inoculated with S. aureus strain 8325-4. Mice underwent slit lamp examination (SLE) at 1, 3, 5, 7, and 9 days after infection and were killed. Histopathologic analyses, determination of bacterial colony-forming units (CFU), and myeloperoxidase (MPO) activity assays were performed at each time point.

RESULTS S. aureus keratitis developed in both BALB/c and A/J strains of mice, but not in C57BL/6. The BALB/c and A/J strains demonstrated greater susceptibility to infection, as evidenced by significantly higher SLE scores and more viable bacteria per infected eye than in C57BL/6 mice at 5, 7, and 9 days after infection (P <or= 0.0001). Histopathologic analysis and MPO assays of infected A/J mice both revealed an influx of polymorphonuclear leukocytes (PMNs). Histology demonstrated presence of leukocytes in the aqueous humor, migration of PMNs into infected tissue, corneal erosion, and edema in the eyes of infected A/J mice. Whereas infected BALB/c mice demonstrated both PMN migration and corneal edema, eyes of infected C57BL/6 mice failed to show even mild histopathologic changes.

CONCLUSIONS These studies demonstrate the establishment of Staphylococcus keratitis in the mouse eye. This model should provide for a large range of future studies that are currently unavailable in the rabbit keratitis model, particularly those requiring a genetically altered host or specific immunologic reagents.