Pathogenesis of Staphylococcus in the rabbit anterior chamber.

Purpose: To investigate the host defense against Staphylococcus in the rabbit anterior chamber.

Methods: The bactericidal activity of rabbit aqueous humor was investigated in vitro. Rabbit anterior chambers were injected with viable Staphylococcus aureus or Staphylococcus epidermidis (1,000 or 500,000 colony-forming units [CFU]), killed bacteria, culture supernatants of either organism, or purified S. aureus alpha-toxin. CFU as well as phospholipase (PLA(2)) and myeloperoxidase (MPO) activities of aqueous humor were determined up to 25 hours postinfection (PI).

Results: The number of viable S. aureus or S. epidermidis was significantly reduced when incubated with aqueous humor for 30 minutes (P
Conclusions: This study demonstrates that aqueous humor has a potent host defense capability and that S. aureus, but not S. epidermidis, triggers a PLA(2) response in the rabbit anterior chamber that appears to be due to alpha-toxin.