Genomic techniques for identification of Leptospira strains

Within the Leptospiraceae family, the genus Leptospira is divided into the pathogenic L. interrogans sensu lato and the saprophytic L. biflexa sensu lato. Based on DNA-DNA hybridization, L. interrogans sensu lato has been shown to contain 7 different genomic species. Each genomic species contains numerous serovars. Pulsed-field genetic studies performed during this work demonstrated a great heterogeneity of serovars, within genomic species, based on restriction length polymorphism analysis. In contrast, an identified serovar, despite the time and region of isolation, has been shown to be highly stable in its genomic structure. The most likely reasons for this finding include the long generation time of these bacteria and the lack of acquisition of heterologous DNA. New identification techniques, based on gene amplification, have been used for Leptospira strains. These techniques represent the first available to facilitate the study of the epidemiology of Leptospira.