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Effect of Staphylococcus aureus Bacteria and Bacterial Toxins on Meningeal Permeability In Vitro
  1. Wolfgang C. Ummenhofer, M.D.,
  2. Ann E. Stapleton, M.D. and
  3. Christopher M. Bernards, M.D.
  1. From the Departments of Anesthesiology and Medicine, University of Washington, Seattle, Washington.
  1. Reprint requests: Christopher M. Bernards, M.D., Department of Anesthesiology, Box 356540, University of Washington, Seattle, WA, 98195.


Background and Objectives Epidural catheterization is associated with a significant bacterial colonization rate and occasionally frank infection. During epidural space infection, decreased analgesia despite increased epidural opioid doses has been described. One possible explanation for this observation is that bacterial infection decreases meningeal permeability. The purpose of the study was to determine whether Staphylococcus aureus bacteria, the most common organism causing epidural space infection, or S. aureus toxins alter meningeal permeability.

Methods Spinal meninges of M. nemestrina monkeys were mounted in a previously established in vitro diffusion cell model and exposed to S. aureus toxins A, B, and F. Simultaneous transmeningeal fluxes of mannitol and sufentanil were measured before and after toxin exposure and compared to controls. In a second series of experiments, diffusion cells were inoculated with live S. aureus bacteria in suspension and the permeability of sufentanil was investigated.

Results Staphylococcus aureus toxin-A increased the transmeningeal flux of mannitol but not sufentanil. Toxins B and F did not alter the meningeal permeability of either drug. Inoculation with live S. aureus bacteria increased the transmeningeal flux of sufentanil by 115 ± 21% (P = .032).

Conclusions These data demonstrate that S. aureus alpha-toxin and live S. aureus bacteria can increase meningeal permeability. Thus, clinical observations of decreased epidural analgesia in the face of bacterial infection cannot be explained by decreased meningeal permeability. Reg Anesth Pain Med 1999: 24: 24–29.

  • epidural analgesia
  • epidural abscess
  • infection
  • meningitis
  • M. nemestrina
  • S. aureus.

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  • This work was performed at the University of Washington, Department of Anesthesiology, Seattle, Washington, and was supported by a grant from the National Institute on Drug Abuse (ROI DA 07313–04A2). Monkey tissues were obtained from the Regional Primate Research Center at the University of Washington, supported by NIH grant RR00166.

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