Treponema Ruminis Sp Nov., A Spirochaete Isolated From The Bovine Rumen

A novel bacterium, strain Ru1(T), was encountered during a survey of spirochaetes living in the gastrointestinal tract of ruminants. Comparative analysis of 16S rRNA gene sequence data indicated that strain Ru1(T) clustered within the genus Treponema but shared at most 86.1% sequence similarity with other recognised species of the genus Treponema. Further phylogenetic analysis based on partial recombinase A (recA) gene sequence comparisons, together with phenotypic characterization, also demonstrated the divergence of strain Ru1(T) from other recognised species of the genus Treponema. Microscopically, strain Ru1(T) appeared as a very small, highly motile, helical spirochaete with eight periplasmic flagella in a 4:8:4 arrangement. It exhibited C8 esterase lipase, leucine arylamidase, beta-galactosidase and beta-glucosidase activity. A distinctive, serum-independent growth pattern was also observed, characterized by colonies with an absence of the local haemolysis that is typical of many pathogenic treponemes. On the basis of these data, strain Ru1(T) is considered to represent a novel species of the genus Treponema, for which the name Treponema ruminis sp. nov. is proposed. The type strain is Ru1(T) (=DSM 103462(T)=NCTC 13847(T)).