Characterization of serovars of the genus Leptospira by DNA hybridization with hardjobovis and icterohaemorrhagiae recombinant probes with special attention to serogroup sejroe.

Recombinant DNA probes derived from genomic libraries of serovars hardjobovis and icterohaemorrhagiae were applied for the characterization of leptospires. Differences in hybridization signals in combination with the banding pattern appear to provide good characteristics for strain typing. The banding patterns were easy to distinguish, since the recombinant DNA probes hybridized with a limited number of fragments. They were also indicative of genomic relationships between serovars. The probes suggested the existence of four subgroups with extensive genomic homology within the serogroup Sejroe. A number of serovars outside the serogroup Sejroe showed genomic homology with these subgroups. Amplification with the polymerase chain reaction showed a correlation with the genomic homologies demonstrated by Southern analysis. Knowledge about genomic relationships between leptospiral strains, as revealed by Southern analysis, may lead to a more rational approach for primer selection for polymerase chain reaction or cloning of particular genes.