Taxonomic Study of Helically Coiled, Sporeforming Anaerobes Isolated from the Intestines of Humans and Other Animals: Clostridium cocleatum sp. nov. and Clostridium spiroforme sp. nov.

Thirty-three anaerobic, gram-positive, helically coiled microorganisms, of which 26 were freshly isolated from the intestinal contents of humans, mice, rats, and chickens, were the subjects of a taxonomic study. These and 48 freshly isolated Clostridium ramosum-like, noncoiled organisms were found to belong to the genus Clostridium because of their sporeforming ability. They were divided into five groups on the basis of numerous biochemical properties, the guanineplus-cytosine (G+C) contents of their deoxyribonucleic acids, and their deoxyribonucleic acid homologies. Strains of group I had straight cells and a G+C content of about 28 mol% and were identified as members of C. ramosum. Cells of the strains in the other groups were coiled. The strains of group II had a G+C content of about 28 mol% and were regarded as belonging to a new species, Clostridium cocleatum, of which strain 150 (= ATCC 29902 = NCTC 11210) is designated the type strain. Those of group III had a G+C content of about 27 mol% and were placed in Clostridium spiroforme sp. nov., of which strain VPI C28-23-1A (= ATCC 29900 = NCTC 11211) is designated the type strain. The single strain of group IV, VPI C22-44-2 (Eubacterium AQ of Moore and Holdeman), had a G+C content of 35.8 mol% and was regarded as a new but unnamed organism in the genus Clostridium. Those of group V, including the original strains of this sort reported by Fitzgerald et al., had a G+C content of about 46 mol% and were also considered to be a new but unnamed organism in the genus Clostridium.