Studies on the Nutrition and Metabolism of Pasteurella pestis.

Abstract

Although Pasteurella pestis has been the subject of a great deal of medical and immunological research, very little work has been done on the physiology of the organism itself. During recent years, attempts have been made to apply technics used in the study of bacterial metabolism to certain pathogenic organisms. The experiments reported in this paper were designed to establish the basic growth requirements of the plague bacillus, and to investigate to some extent the nature of its dissimilatory processes.

Rao 1 claims that 3 amino acids, cystine, phenylalanine, and proline, are essential for the development of P. pestis, and that haematin and riboflavin may be considered as accessory growth factors. However, he does not give evidence that the organism can grow with a mixture of these compounds alone, and provides neither a carbon nor a nitrogen source other than amino acids in most of his media. In an excellent study dealing with the nutrition of the members of the genus Pasteurella, Berkman 2 could find no effect of 12 nutrilites on the development of their strains of P. pestis in a medium containing glucose as well as a mixture of amino acids.

Experiments were carried out in this laboratory and at the Hooper Foundation for Medical Research with a non-pathogenic strain (1122) of P. pestis, and with 3 selected pathogenic strains: 337 (from India), and “Yreka” and “Shasta” from California. Since glucose was found to be the best carbon source and ammonium salts an excellent nitrogen source for all organisms tested, the basic medium was prepared with 0.2% glucose, 0.1% NH₄Cl, 0.05% MgSO₄ 7H₂O, 0.005% FeCl₃, .001% CaCl₂, and M/30 Sorensen KH₂PO₄-Na₂HPO₄ buffer at pH 7.0. Five ml amounts of the basic medium were dispensed in 17 mm test tubes to insure a fair degree of aeration without agitation.