Gram-Positive Non-Sporulating Anaerobic Rod-Shaped Bacteria of the Intestinal Tract

Abstract

The investigation served further to establish that the gram-positive non-sporulating anaerobic bacteria of intestinal origin, which were the chief object of study here, should not be classed with the gram-negative, non-sporulating anaerobes of similar origin, the so-called "bacteroides" group; and that they constitute a more or less homogeneous group of their own, which is closely related to Eggerth''s Bacteroides bifidus and Orla-Jensen''s Bacterium bifidum. On the basis of cell morphology and cultural and physiol. properties, these organisms are definitely linked with the lactobacilli, particularly the known intestinal forms, L. acidophilus and L. bifidus. A study of respiratory enzymes also revealed a close relationship. Colony size and morphology served, on the whole, to separate the different groups from each other. Sero-logical tests were of limited value. The skin test (Arthus phenomenon) had some merit in separating the gram-positive anaerobes from the facultative groups of various origin, and was in fair agreement with the complement fixation tests. Relation of free oxygen to growth constitutes the most important criterion for differentiation from the other lactobacilli.