title: The porcine intestinal spirochaetes: identification of new genetic groups.
abstract: The weakly beta-haemolytic isolates were divided into 56 electrophoretic types (ETs), contained in three distinct genetic groups (A,B and C). Group A corresponded to the genus Serpulina, and could be divided into three divisions. It contained 17 weakly haemolytic isolates in divisions b and c, as well as all 98 isolates of S. hyodysenteriae, located in division a. All seven weakly beta-haemolytic isolates that produced indole and had alpha-glucosidase but not alpha-galactosidase activity fell into division b. These spirochaetes may represent a distinct species. The other ten weakly beta-haemolytic spirochaetes, in division c, fitted the description of S. innocens. Group B contained 17 of the weakly beta-haemolytic isolates (18.9%) in ten ETs. Isolates in this group differed from typical S. innocens in that they lacked alpha-galactosidase activity. Group B represented a distinct group of weekly beta-haemolytic spirochaetes, which may constitute a new genus. Group C contained 56 of the weakly beta-haemolytic isolates (62.2%) located in 29 ETs. The original isolate from "spirochaetal diarrhoea" (P43/6/78-Taylor et al., 1980) was located in this group, together with Australian isolates from a similar condition. Spirochaetes in group C were morphologically distinct from those in groups A and B in that they possessed only four, five or occasionally six, subterminal axial filaments, were more slender, and had more pointed ends to their cells. We consider that group C represents a new genus of spirochaetes, members of which may be associated with spirochaetal diarrhoea.
authors.affiliation: School of Veterinary Studies, Murdock University, Australia.
authors.forename: J I
authors.initials: JI
authors.lastname: Lee
authors.forename: D J
authors.initials: DJ
authors.lastname: Hampson
authors.forename: A J
authors.initials: AJ
authors.lastname: Lymbery
authors.forename: S J
authors.initials: SJ
authors.lastname: Harders
mesh_terms: D000483:Alleles; D000818:Animals; D017400:Brachyspira / Q000235:genetics*; D017401:Brachyspira hyodysenteriae / Q000235:genetics*; D008040:Genetic Linkage; D014644:Genetic Variation; D006462:Hemolytic Plaque Technique; D010641:Phenotype; D013143:Spirochaetaceae / Q000145:classification / Q000201:enzymology / Q000235:genetics* / Q000302:isolation & purification / Q000648:ultrastructure; D013552:Swine / Q000382:microbiology*