Diagnosis of swine dysentery and spirochaetal diarrhoea: Part II: Differentiation of intestinal Serpulina by macrorestriction fragment profile analysis.

Genotypic differentiation by means of macrorestriction fragment profile ana lysis using Mlul restriction enzyme was carried out differentiating 41 Serp ulina field strains from swine (38), dog (2) and a rat as well as ten type and reference strains into 40 electrophoretic types. A dendrogram was creat ed using the average linkage between groups method. At a level of 50 % simi larity the patterns could be divided into six groups that roughly correspon ded to the results yielded by cultural and biochemical methods formerly (FE LTRUP et al. 1999). Five of these clusters corresponded to the five known p orcine Serpulina species, one cluster contained the S. pilosicoli isolates from dog and rat included in this study. Interestingly all nine investigate d indole negative, strongly haemolytic isolates were clustered together in one group with the S. hyodysenteriae strains, so that incidence of indole n egative variants of S. hyodysenteriae was confirmed. Because of being group ed together with two S. intermedia isolates, the suitability of B 256 as S. innocens type strain is - in accord to investigations carried out by PETTE RSSON et al (1996) - called in question.