any of various spiral-shaped motile bacteria of the family Spirochaetaceae, certain species, as Treponema, Leptospira, and Borrelia, being pathogenic to humans and other animals, and other species being free-living, saprophytic, or parasitic.
Origin of spirochete
1875-80; < New Latinspīrochaeta. See spiro-2, chaeta-
spirochete spi·ro·chete (spī'rə-kēt') n. Any of various slender, spiral, motile bacteria of the order Spirochaetales, many of which are pathogenic, causing syphilis, relapsing fever, yaws, and other diseases.