PCR amplification from fixed tissue indicates frequent involvement of Brachyspira aalborgi in human intestinal spirochetosis

PCR procedures amplifying portions of the 16S rRNA and NADH oxidase genes o f Brachyspira aalborgi and Serpulina pilosicoli were applied to DNA extract ed from paraffin-embedded human colonic or rectal tissues from 30 Norwegian , Australian, and U.S. patients, 16 of whom had histologic evidence of inte stinal spirochetosis (IS). B. aalborgi-specific sequences were identified b y PCR in 10 of the IS patients (62.5%) but none of the others, while S. pil osicoli sequences were not detected in tissues from any patient. Direct seq uencing of products from three of the positive samples provided further con firmation of the presence of B. aalborgi. B. aalborgi may be a more common cause of intestinal spirochetosis than has been previously thought.