Spirochaetes and Bacteroids

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The phyla Spirochaetes and Bacteroids contain many common but generally unfamiliar organisms. Although the Spirochaetes bring to mind some important pathogens, both groups are common in the environment and as components of the normal flora of animals. Although not specifically related, nor alike morphologically, these two groups share a common metabolic theme; most are saccharolytic, and are often involved in the decomposition of long-chain polysaccharides such as cellulose and chitin. In addition, each group is motile by a mechanism different that the common flagellar propellor most commonly found in Bacteria.