PANTETHINE-REQUIRING BACTEROIDES.

Reeves, Richard E. (Louisiana State University School of Medicine, New Orleans). Pantethine-requiring Bacteroides. J. Bacteriol. 85:1197-1201. 1963.-Growth of a culture of gram-negative streptobacilli, provisionally designated Bacteroides symbiosus, required a preformed source of pantetheine (pantethine or coenzyme A). Five types of organisms were isolated from the parent culture, and all exhibited a pantethine requirement. Pantothenate neither replaced nor spared the pantethine requirement of these organisms. Of the five isolated bacterial types, three were characterized by producing low, medium, and high optical densities, respectively, in a thiomalate medium. A fourth type was distinguished by cells which would not pack upon centrifugation, and a fifth by its high content of stored carbohydrate. Two of the five types seem well-suited to the growth of Entamoeba histolytica in the MS-F ameba-culture system. In addition to pantethine, these organisms required biotin, folic acid, pyridoxine, thiamine, and choline. A minimal defined medium was elaborated for one of the isolated bacterial types. B. symbiosus ATCC 12829 is proposed as a test organism for pantetheine in the presence of pantothenate.