New method for classification of leptospiral isolates belonging to serogroup pomona by restriction endonuclease analysis: serovar kennewicki.

The genomes of leptospiral field isolates belonging to serogroup Pomona were analyzed and compared with those of type strains by cleavage with restriction endonucleases. This new classification method shows differences among these organisms not indicated by the conventional serological typing method. No differences were observed among isolates from the United States, Canada, and New Zealand. Although all isolates selected for this study had been serologically typed as belonging to serovar pomona, the restriction endonuclease analysis indicates that they belong to serovar kennewicki. kennewicki, a serovar of North American origin, has recently been eliminated from the official serovar list because it was found to be indistinguishable from serovar pomona by the serological method.