Differentiation of Bacteroides from Sphaerophorus and Fusobacterium

Abstract

This paper is concerned with new findings in the comparative study of the genera, Bacteroides, Sphaerophorus and Fusobacterium. Victoria blue 4R and barbiturates were found to be effective in differentiating the genera by their discriminative inhibition of the growth. A new character, glutamic acid decarboxylation, was found in Bacteroides but neither in Sphaerophorus nor in Fusobacterium. The procedure for this test was presented. In the classification of newly isolated fecal strains this test and other differential features were compared. An improved method for the threonine deamination test was reported. The use of these characters and tests would be a step in the improvement of the present incomplete classification of gram-negative anaerobic non-sporulating rods.