Hyperreactivity of Coxiella burnetii Infected Guinea Pigs to Subsequent Injections of Bacterial Endotoxins

Abstract

Summary

Guinea pigs infected for 3 days with C. burnetii demonstrated a hyperreactivity to injections of bacterial endotoxins, with deaths occurring 6–24 hours after treatment. The preparative infectious dose of C. burnetii could be as low as 10⁶ guinea pig IP ID₅₀. The reaction has been provoked with 25 μg of Brucella endotoxin while 10 μg of purer preparations from E. coli and S. typhosa have produced a similar response. An optimal period of reactivity existed from 48–72 hours post infection. Formalin inactivated rickettsiae did not prepare animals for this reaction and infected guinea pigs treated with either rickettsial antiserum or Tetracyn could not be provoked by subsequent injections of endotoxin. The gross and microscopic studies of selected tissues taken from hyperreactive animals consistently revealed hyperemia and hemorrhage of the adrenals. The described hyperreactivity appears to be a manifestation of the generalized Shwartzman reaction.