Oral Fusobacteria.

The genus Fusobacterium was proposed by Knorr (1922) for the pointed, nonsporulating, gram-negative, anaerobic bacilli found in the oral cavity. On the basis of morphology, three species were named, Fusobacterium nucleatum, Fusobacterium polymorphum, and Fusobacterium plauti-vincentii. Similarly, Hine and Berry (1937) described three species, based primarily on morphological and cultural characteristics, which were named Fusiformis nucleatum, F. polymorphum, and F. dentium, these species corresponding to Knorr's classification. In the same year, Spaulding and Rettger (1937a, b) divided these oral fusiform bacilli into two major groups. Later B0e (1941) proposed the separation of the organisms into two genera, Fusobacterium and Leptotrichia, because of their distinct differences in cultural characteristics. Jackins and Barker (1951) studied the fermentative processes of the fusobacteria and inferred that F. nucleatum Knorr and F. polymorphum Knorr corresponded to group I of Spaulding and Rettger, and F. plauti-vincentii Knorr to group II. In addition, F. plauti-vincentii appeared to be identical to the organism called Leptotrichia buccalis Trevisan by B0e. The name Fusobacterium plauti-vincentii Knorr was changed to Fusobacterium fusiforme (Veillon and Zuber) Hoffman in the 7th edition of Bergey's Manual of Determinative Bacteriology (1957). Since the status of the taxonomy of the oral fusobacteria is somewhat confused, this investigation was undertaken as an attempt to correlate biochemical, morphological, and cultural characteristics for the purpose of differentiating species of this group.