[Identification of pathogenic and nonpathogenic leptospires by recombinant DNA probe]

A gene bank of L. interrogans serovar lai strain 017 was constructed with plasmid vector pUC 18. Recombinant plasmids designated pDJ 6 and pDJ 8 were screened from the gene bank. Inserted fragments of them are 1.9kb and 2.2kb respectively. Diglabelled 1.9kb inserted fragment of pDJ 6. Results showed that the probe had hybridization with pathogenic leptospires, but it did not have hybridization with nonpathogenic leptospires such as L. biflexa strain Patoc I and Leptonema illini. The probe did not have hybridization with nonhomologous DNA (e.g. human leucocyte and E. coli JM 103), either. So, the recombinant probe is a good tool for distinguishing and identifying genus, species, pathogenic leptospires and nonpathogenic leptospires.