Anaerobic Fusiform-shaped Bacteria Isolated from the Caecum of Conventional Mice

Twenty-four strains of anaerobic fusiform-shaped bacteria were isolated from the caecum of conventional mice. Ten of the isolates belonged to the genus Clostridium , nine to Fusobacterium and five to Bacteroides. The clostridia were put into eight biotypes on the basis of their ability to: hydrolyze mucin and esculin; produce indole and hydrogen; utilize pyruvate, and ferment arabinose, cellobiose, fructose, glucose, galactose, maltose, mannose and N-acetylglucosamine and on the acid end-products of such fermentations. The fusobacteria were assigned to six biotypes based on their ability to hydrolyze casein, mucin and starch, and to ferment arabinose, lactose, maltose and N-acetylglucosamine. Each of the bacteroides was deemed to be a separate biotype because of the differences in their ability to hydrolyze casein and starch, grow in bile medium, utilize pyruvate, and to ferment arabinose, maltose, xylan and N-acetylglucosamine. Five of the Fusobacterium isolates resembled F. russii. The remaining 19 isolates did not resemble previously described species of anaerobic bacteria.