Abstract
Abstract: :
Purpose: To determine the protectiveness of antibody to Staphylococcus aureus alpha–toxin administered before or during corneal infection. Methods: Rabbit antibody to heat–inactivated alpha–toxin was injected into rabbits intravenously or subconjunctivally (N=8, N=4 respectively) either 24 hours before infection or 6 or 12 hours postinfection (PI). At time zero, rabbit corneas were injected intrastromally with 100 CFU S. aureus. Corneal erosion measurements and slit lamp scoring (SLE) were performed at 15, 20, and 25 hrs PI, and the log number colony forming units (CFU) per cornea were determined at 25 hrs PI. Results: Injection of antibody intravenously 24 hours before infection caused significant reductions in the SLE scores at 20 and 25 hrs PI (P = 0.008 and P ≤ 0.0001, respectively). Corneal erosions were significantly reduced in the antibody–treated groups at 15, 20, and 25 hrs PI (P = 0.029, P = 0.0012, P ≤ 0.0001, respectively). Treated and untreated eyes contained approximately 10 million CFU per cornea at 25 hrs PI (P = 0.149). Intravenous injection of antibody at 6 hrs PI caused a significant reduction in the SLE score at 15, 20, and 25 hrs PI (P = 0.0056, P = 0.0008, and P = 0.0026, respectively). Corneal erosions were also significantly reduced at 25 hrs PI (P = 0.016). Subconjunctival injection of antibody at 6 and 12 hrs PI caused a significant reduction in the SLE score at only 25 hrs PI (P = 0.0051). Corneal erosions were significantly reduced at 25 hrs PI (P =0.0038). Injection of antibody during the infection by either the intravenous or subconjunctival routes did not significantly reduce the log number of CFU per cornea (P ≥ 0.149). Conclusions: Passively administered antibody to alpha–toxin was effective in reducing the corneal damage and inflammation occurring in experimental S. aureus keratitis. None. NEI grant EY10974.
Keywords: Staphylococcus • keratitis • microbial pathogenesis: experimental studies