In vitro cultivation of the rickettsial agent of trench fever

Abstract

Although trench fever appears to be endemic in many areas of the world, recognition of the disease has been handicapped by the difficulties of making a clinical diagnosis and the unavailability of a simple laboratory procedure to establish the etiology. The author describes a method for the in vitro cultivation of Rickettsia quintana that provides a relatively simple means for the laboratory diagnosis of trench fever. R. quintana can be propagated with ease from the blood of patients directly on blood agar incubated at 37 degrees C for 12-14 days under a gas tension of 5% CO(2) in air. The number of rickettsiae circulating in the patient's peripheral blood can be quantitated. The protracted rickettsiaemia in trench fever makes for a relatively long period during which blood culture can be usefully employed.In the course of studies with the method described, it was found that erythrocytes contain a factor (or, possibly, factors) essential for multiplication of R. quintana; this factor is cryostable and thermostable and may be haemoglobin. Blood serum also promotes multiplication.