Spiral bacteria of the genus Brachyspira are usually isolated in connection with cases of intestinal spirochetosis, wherein these anaerobic spirochetes cling by one end to the colorectal epithelium forming thus a false brush border. That can be associated with chronic diarrhea, rectal bleeding, abdominal pain, and body wasting, giving a picture of suspect colorectal carcinoma. Metronidazol is the therapeutic of choice. Colonization with brachyspirae is relatively frequent in the developing countries; in our country it comes in consideration in HIV-positive subjects and in homosexuals. The diagnostics of brachyspirae is complicated (as in all spirochetes) by difficulties in cultivation of the agent, so that molecular biology methods are the usual diagnostic tool.

        Key words: intestinal spirochetosis – Brachyspira aalborgi – Brachyspira pilosicoli.