Xylose-positive staphylococci as a cause of respiratory disease in immunosuppressed rats

Abstract

A severe outbreak of respiratory disease was diagnosed during a long—term toxicity study of Cyclosporine A in Sprague Dawley rats. Only rats closed orally with cyclosporine A fell ill, whereas no control animals contracted the disease. The causative agent was found to be Staphylococcus xylosus, a normal inhabitant the the respiratory tract of rats. Under normal conditions this organism is not pathogenic. In the case of immunocompromised animals, however, Staphylococcus xylosus was able to cause disease. The severity of the outbreak could be explained by insufficient hygienic procedures when closing the animals with a common stomach tube.