Human intestinal spirochetosis diagnosed with colonoscopy and analysis of partial 16S rDNA sequences of involved spirochetes.

DNA was extracted from colonic biopsies of 33 patients with and three without evidence of intestinal spirochetosis (IS) in the large bowel. The biopsies were subjected to PCR. A pair of primers, generating a 207 bp fragment, were designed to detect specifically the 16S rDNA gene of Brachyspira. PCR products of the expected size were obtained from 33 samples with histologic evidence of IS. The PCR amplicons were used for sequencing. The sequences obtained were aligned to the corresponding 16S rRNA sequences of five type strains of Brachyspira. The sequences of 23 PCR products were 99-100% identical with the corresponding B. aalborgi type strain sequence. Two cases showed 99-100% sequence similarity with the type strain of B. pilosicoli P43/6/78. Six cases could not be referred to any of the known species of Brachyspira. Two PCR products gave incomplete sequences.