The Genus Fusobacterium
The genus Fusobacterium includes several species of obligately anaerobic, nonsporeforming, motile or nonmotile, Gram-negative rods. Some are slender, spindle-shaped bacilli, while others are pleomorphic rods with parallel sides and rounded ends. Their hab
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CHAPTER 14.12 mu i re t cabosuF
The Genus Fusobacterium TOR HOFSTAD
The genus Fusobacterium includes several species of obligately anaerobic, nonsporeforming, motile or nonmotile, Gram-negative rods. Some are slender, spindle-shaped bacilli, while others are pleomorphic rods with parallel sides and rounded ends. Their habitat is the mucous membranes of humans and animals. During the last decade of the nineteenth century, several authors, among them Miller (1898), Plaut (1894), and Vincent (1896, 1899, 1904), observed spindle-shaped, or fusiform, bacilli in material from both the diseased and the healthy human mouth. Veillon and Zuber (1998), Lewkowicz (1901), and Ellermann (1904) were the first to cultivate fusiform bacilli. Loeffler, in 1884, observed pleomorphic rods in diphtheritic lesions of calves and doves. The same organism, identifiable with the F. necrophorum of today, was cultured by Bang (1890–1891) from necrotic lesions of a number of domestic animals and by Schmorl (1891) from an epizootic in rabbits. The more pleomorphic fusobacteria without tapering ends have been described under different generic names. Examples are Bacteroides, Sphaerophorus, Bacterium, Necrobacterium, Pseudobacterium, Bacillus, Actinomyces, Corynebacterium, Ristella, and Zuberella. The family name Bacteroidaceae was first used by Pribram (1929) for strictly anaerobic rods. Ten years earlier, Castellani and Chalmers (1919) proposed that the genus Bacteroides should only contain obligately anaerobic bacilli that did not form spores. Eggerth and Gagnon (1933) and Weiss and Rettger (1937) excluded the Grampositive rods from the genus. The generic name Fusobacterium was proposed by Knorr (1923) for obligately Gram-negative bacilli that were fusiform. Prévot (1938), who argued that the generic name Fusobacterium (and also the names Bacteroidaceae and Bacteroides) was invalid, used the term Sphaerophorus for the nonmotile, pleomorphic fusobacteria, and the term Fusiformis for the fusobacteria that had tapered ends. The seventh edition of Bergey’s Manual of Determinative Bacteriology (Breed This chapter was taken unchanged from the second edition.
et al., 1957) divided the family Bacteroidaceae into three genera: Bacteroides, defined as rods with rounded ends; Fusobacterium, defined as rods with tapering ends; and Sphaerophorus, defined as rods with rounded ends that showed a marked pleomorphism and where filaments were common. Cell morphology, therefore, had so far been the main criterion for the classification of the nonsporeforming, anaerobic rods. Physiological studies (Beerens et al., 1962; Werner, 1972a; Werner et al., 1971) and studies of DNA base ratios (Sebald, 1962) showed that there was insufficient evidence to separate the genera Fusobacterium and Sphaerophorus. In the eight edition of Bergey’s Manual (Moore and Holdeman, 1974a) the genus Fusobacterium was restricted to anaerobic, nonsporeforming, Gramnegative rods which form butyric acid as a major endproduct from peptone or glucose (without isobutyric and isovaleric acids). Further,
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