Study on the Growth of Rickettsiae

Abstract

Summary Several species of rickettsiae can be propagated in mouse lymphoblast cells grown in uniform suspension in roller tube tissue cultures. Using these cells a system was developed which was well adapted for quantitative studies on the growth of Rickettsia tsutsugamushi. R. tsutsugamushi multiplies in MB III cells in tissue cultures at 37°C increasing about 3-fold in 24 hr. Certain factors influencing this slow growth rate, which is infinitely less than that of bacteria, phage and certain mammalian viruses multiplying under optimal conditions, are discussed. Chloramphenicol added to the R. tsutsugamushi-MB III cell system resulted in rapid reduction in infective titers of the cultures and in rather prompt disappearance of microscopically recognizable rickettsiae from the cells. The respiratory metabolism of MB III cells infected with R. tsutsugamushi was essentially the same as that of normal cells.