OUTER MEMBRANE-ASSOCIATED SERINE-PROTEASE OF INTESTINAL SPIROCHETES

Pathogenic intestinal spirochetes cause damage to the intestinal mucos a of humans and animals by an unknown mechanism. The purpose of this s tudy was to assess the pathogenic intestinal spirochetes Serpulina hyo dysenteriae, Serpulina pilosicoli, and Brachyspira aalborgi and the no n-pathogenic commensal intestinal spirochetes Serpulina innocens and T reponema succinifaciens for protease activity. A partially heat stable , subtilisin-like, serine protease was identified in the outer membran e of all spirochetes and thus may be essential for survival in the int estinal environment. The outer membrane protease may indirectly contri bute to intestinal damage caused by pathogenic spirochetes during asso ciation with the mucosal surface of the host.