A Systematic Study of the Fusiform Bacteria

Abstract

Methods and media for isolation and cultivation of fusiform bacteria were investigated. For securing anaerobiosis, the method of exhausting anaerobic jars by a vacuum pump, and of subsequent rinsing of the jar with CO2, proved to be especially suited. A highly efficient selective medium for isolation was developed. All strains under study exhibited marked resistance to gentian violet; this dye was therefore of particular value for primary isolation. Aqueous extracts of vegetables stimulated growth, potato extract being particularly suitable. Added CO2 definitely stimulated growth of certain types, and 2% CO2 was always introduced into the anaerobic jars. Successful isolations were obtained from normal teeth of man, monkeys, dogs and rabbits; also from cases of Vincent''s angina, lung abscess and from a tonsillar lesion. No cultures were obtained from normal teeth of cats, guinea pigs, rats and mice examined, nor from human or animal feces. A comparative study was made of 53 strains isolated from various sources. It was possible to divide them into 4 types (designated as I-TV), based on morphological, cultural and biochemical characteristics. Agglutination was unsatisfactory for classification. The generic name Fusobacterium, (Knorr, 1922) is suggested for use in place of Bacillus, which is still so generally applied to this group of anaerobes. Pathogenicity of certain strains was indicated as a possibility. Some evidence was also obtained, which pointed to the transformation of fusiform into spirochaetal forms.