The growth of pleuropneumonia-like organisms of human origin: cultivation in the developing chick embryo and an in vitro growth cycle.

Some strains of pleuropneumonia-like organisms (PPLO) of human origin grow quite sparingly in vitro; therefore, attempts were made to determine if these organisms could be sustained better in the developing chick embryo. A semiquantitative comparison of growth on artificial media and in the chick embryo is presented. As pleuropneumonia-like organisms aIe frequent inhabitants of the genitourinary tract and have often been founcd to be associated with pathological processes, as summarized by MIorton et al. (1952), attempts were made to ascertain if any pathological involvement or inerease in mortality could be noticed in the infeeted chick embryo. The only report of the cultivation of pleuropneumonia-like organisms from man has been a recent report by Paine et al. (1950). These workers describe the isolation of a strain of pleuropneumonia-like organisms from the cerebrospinal fluid of a 20 year old male who was suffering from meningitis. This strain was cultured subsequently in the yolk sac. In the studies of the growth of pleuropneumonia-like organisms in the developing chick embryo, as in other investigations, we have had the need of quantitative information on the growth of these organisms in order to be able to choose coriect and reproducible inocula. The only report dealing with this problem is a study by Holmes and Pirie (1936). These investigators estimated the growth of the pleuropneumonia organisms of cattle by plotting glucose utilization and rieduction of methylene blue in the presence of sodium lactate in regard to the age of the cultures. It was found that a rapid increase of the enzymatic functions occurred for two days which leveled off at about three days.