CLASSIFICATION OF ERYSIPELOTHRIX STRAINS ON THE BASIS OF RESTRICTION-FRAGMENT-LENGTH-POLYMORPHISMS

Restriction fragment length polymorphisms of the 16S rRNA genes of Ery sipelothrix strains were studied by cleavage of the chromosomal DNA wi th restriction endonuclease EcoRI, followed by hybridization to a 420- bp internal fragment of the 16S rRNA gene. Thirty-two Erysipelothrix t ype and reference strains were classified, together with seven field s trains. Reference strains of all serotypes and the type strains of Ery sipelothrix rhusiopathiae and Erysipelothrix tonsillarum were included , Nine ribopatterns were observed. Pattern A was represented by 16 str ains and included strains of serotypes 1b, 2 to 8, 11 to 13, 15 to 17, 19, and 23. Pattern B was represented by two strains (serotypes 1a an d 9). Pattern C was represented by five strains (serotypes 5, 6, and 2 1). Pattern D was represented by one strain of serotype 4. Pattern E w as represented by 11 strains of serotypes 2, 7, 10, 20, 22, 24, and 25 . Patterns F, G, H, and I were each represented a single strain of ser otypes 26, 2, 18, and 3, respectively. All the different ribopatterns had some bands in common. Patterns B, C, and D were most similar to pa ttern A, while patterns F, G, H, and I resembled pattern E. Partial se quencing of the 16S rRNA gene of nine selected strains resulted in thr ee different sequences, i.e., the typical E. rhusiopathiae sequence, t he E. tonsillarum sequence, and a third sequence found for two strains . Strains of the same serotype were found to have different ribopatter ns as well as different partial 16S rDNA sequences.