Genetic structure of the genus Leptospira by multilocus enzyme electrophoresis

Thirty strains from the 11 species of the genus Leptospira were studied by multilocus enzyme electrophoresis at 12 enzyme loci, all of which were poly morphic. The mean number of alleles per locus was 6.5. Twenty-five electrop horetic types were distinguished. Grouping of the strains by cluster analys is was in general agreement with species delineation as determined by DNA-D NA hybridization, except for the strains of Leptospira meyeri and Leptospir a inadai, which were scattered throughout the genus, reflecting previously recognized taxonomic uncertainties. Analysis of the clonality within Leptos pira interrogans sensu stricto indicated that this population was relativel y heterogeneous and a lack of gene linkage disequilibrium could not be excl uded. There was a genetic discrimination between the pathogenic species and the saprophytic ones. The phenotypically intermediate species (L. inadai a nd Leptospira fainei) were also genetically separated and were probably clo ser to the saprophytes than to the pathogens.