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

Abstract

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 intraperitoneal ID50. The reaction has been provoked with 25[mu]g of Brucella endotoxin while 10 [mu]g of purer preparations from Escherichia coli and Salmonella typhosa have produced a similar response. An optimal period of reactivity existed from 48-72 hours postinfection. Formalin-inactivated rickettsiae did not prepare animals for this reaction and infected guinea pigs treated with either rickettsial antiserum or tetracycline hydrochloride 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; there was a total absence of bilateral renal cortical necrosis. The described hyperreactivity appears to be a manifestation of the generalized Shwartzman reaction and the pathology noted is in keeping with the observations of others who have studied this reaction in guinea pigs.