Ribotyping and restriction endonuclease analysis reveal a novel clone of Bordetella bronchiseptica in seals

The goal of the present study was to characterize, by ribotyping and restri ction endonuclease analysis (REA), 35 phocine Bordetella bronchiseptica iso lates and to ascertain their relationship to one another and to isolates ac quired from other host species. Thirty-four isolates were obtained in Scotl and during a 10-year period encompassing the 1988 epizootic; the remaining isolate was obtained independently in Denmark. All phocine isolates had an identical Pvn II ribotype unique from the 18 ribotypes previously detected in strains from heterologous hosts. Alternative restriction enzymes, useful for subgrouping strains within P nuu Pi ribotypes, also failed to discrimi nate among isolates from seals. The exclusive occurrence of a single riboty pe of B. bronchiseptica in a particular host species has not been previousl y observed. Similarly, REA based on either HinfI or Dde I profiles did not reveal detectable polymorphisms, although unique patterns were readily dist inguished among a limited number of isolates from other host species. This is the first report demonstrating the utility of REA using frequently cutti ng enzymes for discrimination of B. bronchiseptica strains. These data sugg est that B. bronchiseptica-induced respiratory disease in seals along the S cottish shore may be due to the circulation of a single, unique clone.