title: Staphylococcus Alpha-Toxin Action on the Rabbit Iris: Toxic Effects and Their Inhibition.
abstract: OBJECTIVE
  Staphylococcus aureus infection of the anterior chamber can occur after cataract surgery, causing inflammation and extensive damage to the iris. Alpha-toxin, the most potent S. aureus corneal toxin, was tested as a possible mediator of damage to the iris, and alpha-toxin anti-serum and a chemical toxin inhibitor were tested as potential pathology-reducing agents.
  
  
  METHODS
  The hemolytic activity of alpha-toxin and its inhibition by a chemical inhibitor or anti-serum were quantified in vitro. Purified alpha-toxin, heat-inactivated toxin, or alpha-toxin plus normal serum, alpha-toxin anti-serum, or the chemical inhibitor, methyl-β-cyclodextrin-cholesterol (CD-cholesterol), was injected into the rabbit anterior chamber. Pathological changes were photographed, quantified by slit-lamp examination (SLE) scoring, and further documented by histopathological analysis.
  
  
  RESULTS
  At five hours post-injection, eyes injected with alpha-toxin or heat-inactivated toxin had a mean SLE score of 7.3 ± 0.59 or 0.84 ± 0.19, respectively. Active toxin caused moderate to severe iris edema, severe erosion of the iris, and mild to moderate fibrin accumulation in the anterior chamber. Alpha-toxin plus anti-serum or CD-cholesterol, in contrast to alpha-toxin alone, caused less iris edema and epithelium sloughing as well as significantly lower SLE scores than eyes receiving alpha-toxin alone (p ≤ 0.019).
  
  
  CONCLUSIONS
  Alpha-toxin caused extensive iris damage and inflammation, and either anti-alpha-toxin anti-serum or CD-cholesterol was able to significantly reduce toxin-mediated damage and inflammation.
authors.affiliation: Department of Microbiology, University of Mississippi Medical Center , Jackson, MS , USA.
authors.forename: Angela M
authors.initials: AM
authors.lastname: Arana
authors.forename: Michael A
authors.initials: MA
authors.lastname: Bierdeman
authors.forename: Charles L
authors.initials: CL
authors.lastname: Balzli
authors.forename: Aihua
authors.initials: A
authors.lastname: Tang
authors.forename: Armando R
authors.initials: AR
authors.lastname: Caballero
authors.forename: Rupesh
authors.initials: R
authors.lastname: Patel
authors.forename: Richard J
authors.initials: RJ
authors.lastname: O'Callaghan
mesh_terms: D000818:Animals; D000867:Anterior Chamber / Q000187:drug effects; D019138:Antibodies, Blocking / Q000627:therapeutic use; D001427:Bacterial Toxins / Q000633:toxicity*; D002784:Cholesterol / Q000627:therapeutic use; D015941:Complement Hemolytic Activity Assay; D004338:Drug Combinations; D004487:Edema / Q000139:chemically induced* / Q000473:pathology / Q000517:prevention & control; D005098:Exotoxins / Q000633:toxicity*; D006460:Hemolysin Proteins / Q000633:toxicity*; D056965:Injections, Intraocular; D007498:Iris / Q000098:blood supply*; D007499:Iris Diseases / Q000139:chemically induced* / Q000473:pathology / Q000517:prevention & control; D009389:Neovascularization, Pathologic / Q000139:chemically induced* / Q000473:pathology / Q000517:prevention & control; D011817:Rabbits; D066167:Slit Lamp; D047392:beta-Cyclodextrins / Q000627:therapeutic use
chemical_list: D019138:Antibodies, Blocking; D001427:Bacterial Toxins; D004338:Drug Combinations; D005098:Exotoxins; D006460:Hemolysin Proteins; D047392:beta-Cyclodextrins; C108732:methyl-beta-cyclodextrin; C021091:staphylococcal alpha-toxin; D002784:Cholesterol
keywords: Alpha-toxin; Staphylococcus aureus, toxin inhibitor; anterior chamber; iris