Influence of Various Metabolites on Growth of Coxiella Burnetii in Monolayer Cultures of Chick Embryo Entodermal Cells.

Burnet (1938) and Cox and Bell (1939) cultivated Coxiella burnetii in tissue cultures of the Maitland type. Burnet reported satisfactory results with cultures of pooled chick embryo viscera, but not with skeletal or nervous tissues or single viscera. Cox and Bell noted that, of the chick embryo tissues, yolk sacs yielded best and most consistent growth. However, in both series of experiments, multiplication of the rickettsiae proceeded slowly and reached a peak during the second week after inoculation. Even under the best conditions, tissue cultures appeared to be less susceptible to infection than embryonated eggs. This investigation was prompted by the belief that tissue cultures, although not the most satisfactory means of cultivating C. burmetii, would yield valuable information on the factors influencing its growth. Monolayer cultures of entodermal cells, derived from the avascular membranes of 4-day-old chick embryos, proved to be of value for the study of viruses of the psittacosis group (Weiss and Huang, 1954). The same type of cultures were used for the development of a quantitative method of study of C. burmetii. This paper describes the method and reports a few experiments which contributed to its formulation and improvement. It also illustrates possible applications.3