Abstract
Aims: The aim of the study was to characterize a spirochaete isolated from thelesions of a cow with digital dermatitis (DD).Methods and Results: The characterization was on the basis of its light andelectron microscopic appearance, enzymic profile and DNA sequence analysisof its flagellin and 16S rRNA genes. The spirochaete was 6–8-lm long and 0Æ2–0Æ3 lm in diameter, and possessed seven to eight periplasmic flagella, withthree to five helical turns. The enzymic profile of the bacterium resembles, butis not identical to that of Treponema brennaborense. Its flagellin gene sequencewas identical to that of Treponema phagedenis but distinct from that of anovine spirochaete. Analysis of a 1477-bp region of the 16S rRNA genes indica-ted that this is a Treponema species and that it is indistinguishable from someisolates made from cases of bovine DD in the United States. Finally, electronmicroscopy revealed the presence of myovirus-like bacteriophage particles in allcultures of the treponeme examined.Conclusions: The spirochaete isolate was identified as a Treponema species clo-sely related to some isolates from the United States (by 16S rDNA) and to T.phagedenis (by flagellin gene sequence) and is associated with bacteriophageparticles.Significance and Impact of the Study: The fact that the isolates with the sameor very similar 16S rDNA sequences have been obtained from cases of bovineDD in cattle in different countries at different times, lends further support tothe hypothesis that treponemes play a role in the pathogenesis of this disease arabic 10 English 72