The phylogenetic positions of
Serpulina hyodysenteriae, Serpulina innocens, Serpulina pilosicoli and
Brachyspira aalborgi were studied. Complete 16S ribosomal DNA sequences of these three species and
B. aalborgi revealed that their 16S rDNA sequences were related more than 96.0%. The mol% guanine plus cytosine (G+C) of
B. aalborgi DNA was 27.1, and was similar to those of the 3 members of the genus
Serpulina. The homologous rates using
32P-labeled
B. aalborgi chromosome DNA in DNA-DNA reassociation tests were 22.0% to
S. hyodysenteriae, 19.1% to
S. innocens and 17.2% to
S. pilosicoli. Therefore, we propose to transfer the three species of the genus
Serpulina to the genus
Brachyspira. Descriptions of
Brachyspira hyodysenteriae comb. nov.,
Brachyspira innocens comb. nov. and
Brachyspira pilosicoli comb. nov., and an emended description of
B. aalborgi are given. Phenotypic characteristics of the 4 members of the genus
Brachyspira were also studied. They fermented fructose, galactose, glucose, lactose, maltose, mannose, raffinose and trehalose; however,
B. aalborgi did not ferment raffinose. All of them hydrolyzed esculin but did not produce indole except for
B. hyodysenteriae. The protein profile of
B. aalborgi was different from those of the four strains of
B. hyodysenteriae, B. innocens and
B. pilosicoli, but the heavy bands with molecular sizes of 49.4 and 52.3kDa of
B. aalborgi were quite similar to those of
B. innocens in the points of quantity and molecular size. In immunoblotting tests,
B. aalborgi reacted well with anti-
B. innocens and
B. pilosicoli sera, but reacted weakly with anti-
B. hyodysenteriae serum. Only one heavy band and several faint bands were revealed by the reaction between
B. aalborgi and anti-
B. hyodysenteriae serum, and the heavy band was common among these strains.
View full abstract