Rapid and simplified protocol for isolation and characterization of leptospiral chromosomal DNA for taxonomy and diagnosis.

We have developed a rapid method for the isolation of leptospiral chromosomal DNA which yields DNA of a purity suitable for restriction endonuclease analysis. A small volume (15 to 20 ml) of an exponentially growing culture of leptospires yielded 2 to 4 micrograms of chromosomal DNA. In a 1-day protocol, the DNA was isolated, restricted with endonucleases, and fractionated on an agarose gel. Chromosomal DNA from dinger zones (visible subsurface zones of leptospiral growth) of first semisolid subcultures of field isolates was also isolated and characterized, thus greatly speeding up the diagnostic process.