SURVEY OF INTESTINAL SPIROCHETES FOR NADH OXIDASE BY GENE PROBE AND BY ENZYME ASSAY

NADH oxidase activity has been found in a number of host-associated ba cterial species by previous investigators. NADH oxidase may play an es sential role in the colonisation of the mammalian intestinal tract by diverse bacterial species. In this study, 45 strains of intestinal spi rochaetes were screened for NADH oxidase by enzyme assay and by using an oligodeoxynucleotide probe (5'-ATGAAAGT(TA)AT(TA)GT(TA)AT(TA)GG-3') complementary to the 5'-end of the NADH oxidase (nor) gene from Serpu lina (Treponema) hyodysenteriae B204. The strains surveyed included 18 strains of S. hyodysenteriae, S. innocens strains B256 and 4/71, Trep onema succinifaciens 6091, T. bryantii RUS-1, and 23 strains of unchar acterised (unclassified) intestinal spirochaetes. The uncharacterised spirochaetes had been isolated from the intestinal contents of differe nt animal hosts (human, swine, avian, nutria). NADH oxidase was absent from T. succinifaciens and T. bryantii, but was present in every stra in of S. hyodysenteriae, in the two recognised strains of S. innocens, and in every uncharacterised strain of intestinal spirochaete. Cells of four strains contained NADH oxidase activity but their DNA did not react with the probe. NADH oxidase is a common enzyme for the intestin al spirochaetes included in this survey.