Roseburia cecicola gen. nov., sp. nov., a Motile, Obligately Anaerobic Bacterium from a Mouse Cecum

Strain GMT (type strain), a motile, obligately anaerobic bacterium, was isolated from scrapings of the cecal mucosa of a conventional laboratory mouse. Strain GMT cells were gram-negative, nonsporeforming, slightly curved rods (0.5 by 2.5 to 5 μm) with 20 to 35 flagella inserted into the concave side and, occasionally, into the end of each cell. The flagella appeared as a single fascicle when the cells were examined by phase-contrast microscopy. Glycerol, sorbitol, d-glucuronic acid, d-xylose, d-galactose, d-raffinose, d-glucose, d-maltose, cellobiose, sucrose, starch, and glycogen were growth substrates for this organism. Butyrate, ethanol, CO2, and H2 were products of fermentation of glucose and acetate by growing cells. The guanine-plus-cytosine content of the deoxyribonucleic acid of strain GMT was 42.3 mol%, as determined by the thermal denaturation method. The characteristics of this bacterium indicate that it does not belong to any currently recognized genus. Therefore, for this organism we propose a new genus, Roseburia, and a new species, Roseburia cecicola, in the family Bacteroidaceae. A culture of the type strain (strain GM) has been deposited in the American Type Culture Collection under the number ATCC 33874.