PURPOSE: alpha-Toxin mediates extreme corneal damage during Staphylococcus aureus keratitis. Chemical inhibition of this toxin was sought to provide relief from toxin-mediated pathology. METHODS: Inhibition of alpha-toxin by phosphate-buffered saline (PBS), 0.1% methyl-beta-cyclodextrin (CD), or CD plus cholesterol (0.1%, CD-cholesterol) was assayed by hemolysis of rabbit erythrocytes. Pathologic changes in rabbit corneas injected with 12 hemolytic units of alpha-toxin suspended in PBS, 1% CD, or 1% CD-cholesterol were compared over time. Rabbit corneas injected with 10(2) colony forming units (CFU) of S. aureus were treated from 7 to 13 hours postinfection (PI) with a total of 15 drops of CD-cholesterol, CD, or PBS. Slit lamp examination (SLE) and measurement of erosions were performed at 13 hours PI and bacteria were quantified at 14 hours PI. RESULTS: Toxin-mediated lysis of erythrocytes was inhibited up to 16,000-fold in the presence of CD-cholesterol compared with CD or PBS. Eyes injected with alpha-toxin mixed with CD-cholesterol had, at 7 hours postinjection, significantly smaller erosions than eyes injected with alpha-toxin in PBS or alpha-toxin mixed with CD (P = 0.0090 and P = 0.0035, respectively). Eyes infected with S. aureus and treated with CD-cholesterol had significantly lower SLE scores than eyes treated with CD or PBS (P <or= 0.0103 and P <or= 0.0017, respectively); however, there were no differences in the number of bacteria present (P >or= 0.0648). CONCLUSIONS: CD-cholesterol is a potent inhibitor of alpha-toxin activity in vitro and an effective means to arrest corneal damage during S. aureus keratitis.
PURPOSE: alpha-Toxin mediates extreme corneal damage during Staphylococcus aureus keratitis. Chemical inhibition of this toxin was sought to provide relief from toxin-mediated pathology. METHODS: Inhibition of alpha-toxin by phosphate-buffered saline (PBS), 0.1% methyl-beta-cyclodextrin (CD), or CD plus cholesterol (0.1%, CD-cholesterol) was assayed by hemolysis of rabbit erythrocytes. Pathologic changes in rabbit corneas injected with 12 hemolytic units of alpha-toxin suspended in PBS, 1% CD, or 1% CD-cholesterol were compared over time. Rabbit corneas injected with 10(2) colony forming units (CFU) of S. aureus were treated from 7 to 13 hours postinfection (PI) with a total of 15 drops of CD-cholesterol, CD, or PBS. Slit lamp examination (SLE) and measurement of erosions were performed at 13 hours PI and bacteria were quantified at 14 hours PI. RESULTS:Toxin-mediated lysis of erythrocytes was inhibited up to 16,000-fold in the presence of CD-cholesterol compared with CD or PBS. Eyes injected with alpha-toxin mixed with CD-cholesterol had, at 7 hours postinjection, significantly smaller erosions than eyes injected with alpha-toxin in PBS or alpha-toxin mixed with CD (P = 0.0090 and P = 0.0035, respectively). Eyes infected with S. aureus and treated with CD-cholesterol had significantly lower SLE scores than eyes treated with CD or PBS (P <or= 0.0103 and P <or= 0.0017, respectively); however, there were no differences in the number of bacteria present (P >or= 0.0648). CONCLUSIONS:CD-cholesterol is a potent inhibitor of alpha-toxin activity in vitro and an effective means to arrest corneal damage during S. aureus keratitis.
Authors: Björn Fahsel; Hannes Kemper; Joelina Mayeres; Katrin Anne Becker; Cao Li; Barbara Wilker; Simone Keitsch; Matthias Soddemann; Carolin Sehl; Marcus Kohnen; Michael J Edwards; Heike Grassmé; Charles C Caldwell; Aaron Seitz; Martin Fraunholz; Erich Gulbins Journal: Infect Immun Date: 2017-12-19 Impact factor: 3.441
Authors: Agnieszka K Zielinska; Karen E Beenken; Hwang-Soo Joo; Lara N Mrak; Linda M Griffin; Thanh T Luong; Chia Y Lee; Michael Otto; Lindsey N Shaw; Mark S Smeltzer Journal: J Bacteriol Date: 2011-04-08 Impact factor: 3.490
Authors: Peng Gao; Pak Leung Ho; Bingpeng Yan; Kong Hung Sze; Julian Davies; Richard Yi Tsun Kao Journal: Proc Natl Acad Sci U S A Date: 2018-07-16 Impact factor: 11.205